You're in the Quad-Cities so that gives you a few options of stuff to do in both Iowa and Illinois.
Mississippi River Center
http://www.missriver.org/
If you travel a half hour north there's the Maquoketa Caves State Park.
Anamosa is nearby- maybe 45min drive? Grant Wood Art Gallery, he had a studio there.
If you drove about an hour west, you'd go past Iowa City and there's the Amana Colonies.
http://www.amanacolonies.com/
Across the river in Moline: John Deere HQ.
Depending on when you're there this summer- Le Claire, IA has a tug-of-war game with the rope going across the Mississippi River to a town on the Illinois side.
Iowa tourism center:
http://www.iowalifechanging.com/