I spent 2 hours at My Gym for a 2 year olds birthday party and it was the best fun ever for everyone.
The staff does their best to organize some fun games spaced between free play for the the children while music is played over the loud speaker. There is everything from a ball pit, climbing wall, trampolines and much more for your child to explore.
They have classes for each age group during the week and have parties scheduled at various time slots.
I would highly recommend this for any age. They advertise classes for up to 13 years.