In my area, as some have been mentioned are:
Garden of the Gods (scenery and hiking)
Manitou cliff dwellings (meh, just ok, but cool if you've never been to Mesa Verde can see all you need in 1/2hr)
Pikes Peak (jump on youtube and show them videos of the hill climb race)
Pro Rodeo Hall of Fame (I need to get there someday)
Seven Falls (haven't been there)
Cave of the winds (many many years since I have been, but it's cool)
Whitewater rafting?
Cheyenne Mtn Zoo
Make a stop at the B52 at USAFA and the visitors center. (just make sure you're not packin' heat)
Petersen has a nice display of planes too and if you go during business hours, there is one you can climb into.
Royal Gorge
Is that Shelby Museum still open in Boulder?
There is an antique car museum in Arvada too.
http://www.cusslermuseum.com/Lazer Tag or paint ball
What about that indoor skydiving thing near 470 & I-25
Any local fair would be cheap and fun. El Paso has a demo derby, but I don't recall when it is.
Heck, sounds fun enough I may come with ya!! LOL!