City Treehouse – Chelsea
129A West 20th Street between Sixth and Seventh Avenues
Ages 3 months-8 years
This beautiful, nature-themed play space features a two-story tree house complete with a slide, and a multilevel water table and stream.
Sibling deal: A family pass costs $40 per day regardless of how many kids you have. Visit the website for open play hours and to reserve your spots since it often fills up.

Sensory City – Long Island City
1-11 44th Road between 9th and 10th Streets, Suite 402
Ages 1-8
We raved about this state-of-the-art sensory gym when we visited in 2013. Highlights include a rock climbing wall with ropes, a ball pit, a two-story castle for imaginative play with an exit slide, swings, a zip line and toys.
Sibling deal: $30 for the first child, half price for siblings. Visit the website for open play hours. You must reserve your spots in advance via email or phone: 718-433-4434.

Klub4Kidz – Willamsburg
159 North 4th Street between Bedford and Driggs Avenues
Ages 0-12
Unlike most kiddie gyms, this one is fun for toddlers through tweens. Attractions include a four-story indoor playground featuring a zip line, crawl tubes, mazes and slides; an 18-foot rock climbing wall and a separate padded toddler room for the under 3 set.
Sibling deal: Open play pricing varies depending on which attractions your kids want to try. But if you've got a toddler and a tween, you pay just $5 more for the older kid and everyone pays $10 on Tuesdays. Visit the website for open play hours.

ArtsCetera – Cobble Hill
310 Atlantic Avenue between Smith and Hoyt Streets
Ages 0-4
Tots can enjoy 90-minute open play sessions featuring toys, blocks, trains, board books and a short sing-along.
Sibling deal: $10 for up to two siblings. Visit the website for open play hours.

Building Bridges Play Space – Brooklyn Heights
Congregation Mount Sinai, 250 Cadman Plaza West at Clark Street
Ages 2-5
This nonsectarian preschool offers drop-in play in its classroom, which is filled with manipulaties, pretend play stations, blocks, books and art supplies.
Sibling deal: $20 for first child, half price for siblings. Visit the website for open play hours.

Drop-In Center at Congregation Beth Elohim – Park Slope
274 Garfield Place near Eighth Avenue
Ages 0-2
Another popular Park Slope tot spot where little ones can tumble and play with educational toys.
Sibling deal: $10 for first child, $7 for siblings. Visit the website for open play hours.

Juguemos a Cantar Drop-In Play Space – Park Slope
438 Sixth Avenue at 9th Street
47 Sterling Place at Sixth Avenue
Ages 0-4
With two Park Slope locations on opposite ends of the neighborhood, this Spanish immersion program opens up its play spaces to the public at designated hours on weekdays.
Sibling deal: $10 for first child, $2 for siblings. Visit the website for open play hours at both outposts.

Brooklyn Arts Exchange – Park Slope
421 Fifth Avenue between 7th and 8th Streets
Ages 1-4
Tots can navigate hoops and tunnels, color, play with balls and read books at this under-the-radar gem.
Sibling deal: $10 per family. Visit the website for open play hours.

PLAY – Greenpoint
33 Nassau Avenue between Guernsey and Dobbin Streets
Ages 0-5
Preschoolers can hit the play sets, activity stations like a food market and laundry set, and romp around the tumbling gym. There's also a separate baby area where infants can crawl and explore safely.
Sibling deal: $20 for first child, $10 for siblings. Visit the website for open play hours.

Check out our Indoor Activity Guide for other great places to play inside.