Dynamite Gymnastics is THE place for a birthday party. You can get this huge inflatable caterpillar and they have a long trampoline that the kids can run down and jump into their foam pit. It is AWESOME!

Star Wars Lego party. You can get Legos on loan from sirbrixalot.com. It was awesome.

Bounce U in Rockville is a popular party location for this age group at my son's school.

Color Me Mine

We did a Mad Science party for 20 kids. It was not cheap, but it was a super huge hit.

Laser Tag is popular with that age too.

Movie?

Ice skating?

Gymnastics?

Barry's Magic Shop?

Bowling?

depends on what he/she likes:

Nature Centers do b-day parties:
http://www.montgomeryparks.org/nature_centers/index.shtm

Bounce U/Pump it Up

Paint Your Own Pottery

Any ideas in the Bethesda/Rockville area for 7 year old birthday party for 15-20 kids? Thanks in advance.