One of the better places to ride if you are near Naperville. Lots of fire roads, with tight technical single track in other places. Though the majority of riding is on fire road, it's still fun and can be used to build endurance. Connect the fire roads with singletrack to make numerous loops. Better riders can do multiple loops while beginners will not be overly challenged.
How to get there:
Off 95th street heading east from Naperville. Enter Knoch Knolls Park, find trails and ride!
The Frisbee golf course there makes an intriguing post ride activity.