There's a small park near me with lots of short and steep hills (compared to what's around). I'll do a 2.75 mile lap, and I'll get about 260 ft elevation gain per lap.
The downside is that my right hand will cramp up from all the shifting.
Usually I'll have to go 50 miles to get as much climbing as I get in 17 miles / 1 hour there doing laps.
Check out the speed and elevation graphs:
http://connect.garmin.com/activity/172317602
TL;DR : Illinois is flat.