The Coralville and Iowa City Recreation systems are also very loaded down with kid friendly things.
I know growing up in Coralville ,there were TONS of activities my parents would enroll me in (to get rid of me for a few hours!).
Do they still do McBride Daycamp? I use to go to that every year and loved it. I'm not sure who sponsored the program, but a lot of kids went, and it was a very awesome experience. I looked forward to it every year. It takes place out in the state park at the lake - very wooded, very hands on, nature, etc. I think it ran for one week or two weeks depanding on which section you took (meadows, forests, water, etc). You could take multiple sections as well.
Camp Wapsi(?) was also a big one in eastern Iowa.
check these out as well....
North Liberty Recreation
The Iowa City Public Library also has a lot of activities, or you can go out to the Coralville Res. and go to the beach, the fossil gorge, tons of hiking, boating, etc.
There's the Herbert Hoover Library just to the east of Iowa City with a replica of the place where Hoover grew up, and lots of stuff you can wander through, be outside.
the University of Iowa also has a couple museums, like the Natural History Museum that we use to love going to as kids.
Coralville just built a brand new library, and they've always been very hands on with kids (that and the Rec center is awesome). There's the Childrens Museum in Coral Ridge Mall, the really nice outdoor pool in Coralville, which is right by the Rec Center, a bunch of playground equipment, lots of parkland and a big pond that's full of ducks looking to be fed all summer.
ICPL - Parents & Kids
Adventure Tours Iowa City IA Iowa + National Parks - City Guide
Coralville also has a 10 week program (not 10 full weeks, just available on a weekly basis) called Camp Coralville...it's in this link about halfway down.
Camp Coralville