Kids' Birthday Parties in NJ & NYC — Genius Gems

The birthday party you get to enjoy too.

A private party room, experienced party leaders, one take-home project for every kid, magnetic-tile building and games, and pizza and juice for the kids. You bring the cake — we handle everything else.

Book your party

A dozen kids inside the giant magnetic-tile wall they built at a Genius Gems Millburn birthday party, balloons overhead
Kids cheering in front of the rainbow tile castle they built together at Genius Gems Millburn
The birthday song — a boy blowing out the candles on a sprinkle cake at Genius Gems
The Genius Gems NYC party room — a dozen kids at a long white table working on their project
Three party guests in wristbands holding up the glitter tiles they designed at Genius Gems NYC
The glow-in-the-dark room at Genius Gems NYC — kids building under blacklight
Two girls making purple glitter slime at a balloon-decorated party table in NYC
A party guest stretching the silver glitter slime she just made
Party guests with drinks at the Design Bar counter at Genius Gems NYC
Ages
5+ · 4-year-olds with a full rent-out
Party length
1.5 hours minimum
Included
Pizza, juice & a take-home project
Run by
Dedicated party leaders

Choose your package

Every package includes a dedicated party room, the leaders, one take-home project for every kid, and pizza and juice for the kids. Each card shows exactly how many kids and adults are included — and how big the party can grow for an additional cost.

Millburn, NJ

New York City

Every package includes

Three party guests in wristbands holding up the glitter tiles they designed

How the party goes

Parties run 1.5 hours minimum — longer with extra time or a full rent-out. Here's the shape of it.

  1. Arrive to a room that's ready — When guests walk in, your private party room is already set up and our experienced staff take it from there.
    A decorated Genius Gems party room with pink balloons on every table
  2. Build and play — in your room — In Millburn we bring the fun to you: our staff lead magnetic-tile building and games right in your private party room (full-venue parties get the whole floor). Big builds, big cheers, everyone involved.
    Kids cheering in front of the giant rainbow tile castle they built together
  3. Make the take-home project — Then the tables turn into a workshop for the one project you chose — glitter tiles or slime — with a party leader guiding every step.
    Two girls making purple glitter slime at a balloon-decorated party table
  4. Make the take-home project — In NYC the project comes first: the one project you chose — glitter tiles or slime — at the table with a party leader guiding every step. (Premier Plus parties can flip the order if you'd like.)
    The birthday song — candles going out on a sprinkle cake
  5. Build and play in the Glow Room — Next, our staff walk the kids into our Glow Room for magnetic-tile building and games — big builds, big cheers, everyone involved.
    Three boys with glitter medals and goodie bags at the end of a party
  6. Food and cake — The kids wash their hands while staff reset the room, then it's pizza and your cake or cupcakes — though we're happy to accommodate whatever you have in mind. Then the song. Bringing goody bags? We'll hand them out — or order ours as an add-on.
    A decorated Genius Gems party room with pink balloons on every table
  7. Back to your party room for food and cake — While the kids are in the Glow Room, staff reset your private room — then everyone washes up at the room's own sink and settles in for food: typically pizza and your cake or cupcakes, though we're happy to accommodate whatever you have in mind. Then the song. Bringing goody bags? We'll hand them out — or order ours as an add-on.
    Kids cheering in front of the giant rainbow tile castle they built together

The take-home project

Every package includes one project for the whole party — choose glitter tiles or slime, and every kid makes one. Engineering builds and themed projects are add-ons that take its place.

Make it yours

Themes, food, wow-factor extras and favors — all added after booking in your party dashboard, with prices shown as you go.

A room that's actually yours

Your party room is reserved for your group for the full party, set with tables, tablecloths and servingware before you arrive. Full-facility packages take over the whole space.

The Millburn party room — a dozen kids inside the magnetic-tile wall they built, under a Happy Birthday banner
The NYC party room set for a party — long white tables, pink balloons on every table, pizza and juice out

Parties at Genius Gems

A grinning party guest in front of foil balloon letters
The birthday face.
Nine kids waving from behind a rainbow tile wall
Every party builds something big.
Four laughing kids in party hats behind a tile castle
Party hats optional, castles mandatory.
Party leaders helping guests at the glitter-tile table
Our party leaders run every station.
A guest stretching pink slime at the party table
Slime, perfected.
The Millburn party room set with balloons and confetti tables
Millburn, ready for guests.

Good to know

Frequently asked

Booking & timing

How do I book a party?
Right here — pick your location, package and time. Your party coordinator calls the week of the party — the Sunday before, or by Wednesday at the latest, when you'll actually have your numbers — to confirm the details and any add-ons. Extras are paid the Thursday before your event.
How do I book a party?
Right here — pick your location, package and time. Our event coordinator reaches out at least two weeks before the party to confirm the details and any add-ons, so you know exactly what to expect, and you'll have the chance for a 30-minute planning call. Extras are paid the Thursday before your event.
How far ahead can I book?
Up to four months ahead, at both locations — the calendar shows every open slot in that window. Weekend slots go first, so book early if your date matters.
How soon can I arrive?
You may arrive 20 minutes before your scheduled party. Our staff may still be cleaning up from the previous party or event.
How soon can I arrive?
You may arrive 15 minutes before your scheduled party. Our staff may still be cleaning up from the previous party or event.
How soon can my guests arrive?
To keep everything on schedule, we kindly ask that guests arrive at the party start time.
Would it be possible to book a party for a time or date not listed on the website?
Yes — email us and we'll do our best to accommodate you.
What if the birthday child gets sick?
In extenuating circumstances such as sickness or injury we'll do our best to reschedule at a mutually convenient date. As per our cancellation policy, we're not able to offer refunds for party cancellations.

Guests & head count

Are adults included?
Yes — every package includes a set number of adults (it's on each package card; Premier includes 16 adults with 16 kids). Each extra kid includes 1 more adult at no extra charge, up to the package maximum (22 kids and 22 adults for Premier). If more adults come than children, the extra adults are $25 each.
When do I need to give my final head count?
Final numbers are due by the Wednesday or Thursday before your party. That's when we set the room, order the food and pack the projects — Friday is too late for us to have everything ready.
When do I need to give my final head count?
Final numbers are due by the Wednesday or Thursday before your party. That's when we set the room, order the food and pack the projects.
Can an Elite Drop-Off party have more than 18 kids?
The Small Party Room holds up to 18 kids, so 18 is the Elite maximum. If your list might be bigger, an upgrade to a Premier party in the large party room is possible only when that room is still available — and it often isn't. If you're unsure of your count, we recommend booking a Premier party from the start.
Can I add kids or adults after the final head count?
Yes — last-minute additions are welcome. They're charged at the end of the party at the extra-guest rate plus a $10 late-addition premium: $50 per additional kid and $35 per additional adult on Premier (other packages follow the same rule on their own rates).
Can I add kids or adults after the final head count?
Yes. Kids added in advance — any time before midnight the night before your party — are $40 each on Premier, VIP Glow and Premier Plus. Kids added on the day of the party are $50 + tax each, charged at the end of the party. Extra adults are $25 each, whether added in advance or on the day.
What happens if fewer guests arrive than I paid for?
If you pay for additional kids or adults and fewer show up, there are no refunds or credits.
What happens if more guests arrive than I paid for?
If more kids or adults come than expected, the additional guest price is paid at the end of the party — extra kids at the same-day rate ($50 + tax each on Premier, VIP Glow and Premier Plus) and extra adults at $25 each.
Can I count children as part of the adult guest number?
No — children and adults can't be swapped. If there are more children or adults than your party's initial number, the respective additional guest price is paid at the end of the party.
What if my guests stay past the end time?
We're happy when guests love the space! Families are welcome to buy tickets to stay and play. If they don't, the additional time fee is charged automatically — you have a 15-minute grace period to pack up.

Food, drinks & deliveries

Am I allowed to hire outside vendors or caterers?
We provide comprehensive in-house services and catering to keep the event smooth. Outside vendors or caterers are welcome with advance approval and a service fee — and we keep it simple: give us the vendor's business name and email address and we handle the paperwork. They complete everything, including the certificate of insurance, in a few clicks.
Can I have cake or balloons delivered for the party?
Deliveries must be on the day of the event, during business hours, and we must be notified in advance. We don't have fridge or freezer space for cakes, and we can't be responsible for delivery mishaps. Talk to our event coordinator if you'd like to drop decorations off early.
Can I have cake or balloons delivered for the party?
Deliveries must be on the day of the event, during business hours, and we must be notified in advance. We can't be responsible for delivery mishaps. Talk to our party coordinator if you'd like to drop decorations off early.
Can my cake be refrigerated?
Usually, yes — our party staff can refrigerate a cake if we know ahead of time, so please mention it when you plan the party so we can make the space. Ice-cream cakes aren't a good fit.
Do you offer kosher pizza?
Yes — kosher pizza can be ordered through us for the party at an additional cost; ask your coordinator and it's added to your order. More generally, families who need to bring in food for religious reasons are welcome to — just let us know in advance so we can plan the table.
Can adults have a drink at the party?
In NYC, yes — we hold a beer and wine license. Choose a mimosa or bellini bar, a beer and wine package, or an à la carte bar in your party dashboard after booking.

The space & the practical stuff

What are the table sizes and room setup like?
Tables are 32 in. × 32 in. and 29.5 in. tall. Typically 9 tables are used for the take-home activity and eating, with 2 more as the cake/dessert table. Elite parties include up to 8 tables plus 1 cake table. Specific layout requests are welcome in advance.
What are the table sizes and room setup like?
Bringing tablecloths? Email us and we'll send you the exact table measurements and the number of tables set for your party size. Specific layout requests are welcome in advance.
Can I hang decorations?
Yes — with the painter's tape we provide, which comes off our walls cleanly. Please don't use glue dots, regular tape or glue. Weighted balloons are welcome; confetti and sparklers aren't.
What if I leave personal party items behind?
It happens! Please pick up your items within 48 hours at the location; after that they're donated per our lost & found policy.
What is your tipping policy?
Tips are never expected or required, but always appreciated. If you'd like to leave something for your party staff, any amount you think is appropriate works — cash or electronic tips are both welcome.

Let's celebrate

Pick your location, choose a package and a time, and you're booked in minutes.

Questions first? Email information@geniusgems.com