Check out the Bike Iowa page for bicycling events in the state of Iowa. The official Kidical Mass website offers great resources on family bike blogs, tips for planning a Kidical Mass ride, and a list of rides in various other states, should you want to join in on one elsewhere. You can also find more events and resources on biking in Ames, IA on the Ames Bicycle Coalition website and FB page.
To read more about how families are incorporating bicycling into their daily lifestyle, check out these blogs dedicated to biking with kids and living car-lite:
Family Bike Blogs: