B-day Party Venues

I'm in Wheat Ridge, and our local rec center rents out their activity rooms and also does swimming parties, Wii game parties, etc. I know the prices vary drastically from one rec center to another, but I found our local rates to be very reasonable so it might be worth checking out.

We just did a swimming party for my son's birthday in October, and we were able to have 18 swimmers (with unlimited access to the pool for the entire day), 30 people at the party, and an hour in an activity room for $50 total! Even adding in our expense for party favors, crafts for the kids, cake, etc. we still spent way less than we have ever done in the past for a party - and the kids loved getting to swim all afternoon.

White Fence Farm? Littleton Historical Museum or 4Mile Park? Not sure what they would be like in December, but you could check them out.

Monkey biz.... just went with my girls to a party there and it was great! They run around like animals and bounce, jump, slide ect for an hour, then they take you into a party room, serve up cupcakes and then clean up the mess!
It was a great idea!
Not sure how affordable it is for some folks, but to me I thought it was great! If you truly look at all you spend on a home party or some other places it is right in line..

Jump Street - giant room of trampolines!
JungleQuest - ziplines and wall climbing
Monkey Business - giant bouncy stuff
We always used Englewood Park and Rec - great pool with fun Frog slide and walk-in shallow end for smaller or non swimming children. Also a nice party room.
Bowling