Gnaw Bone Camp offers a long and fairly challenging ride. There is lots of relentless climbing that will challenge all but the truly fit riders. The way back down isn't much easier either. Steep technical descents make the entire ride a skills tester, but a fun ride.
How to get there:
From Bloomington, take HWY 46 to HWY 135 South. Follow 135 South for about 2 miles to Gnawbone Camp. Turn to the left at the sign and park near the store.
You can buy a map at the general store.