Roly Poly is my personal favorite trail in Northern Allamuchy's trail system. Coming out of the Cardiac/Ditch climb (heading southwest), make a hard left onto an almost impossibly punchy climb up strewn rocks. Then, veer left at the next intersection and you'll be on the trail.
Roly Poly is relentless with the amount of rock rollers it will throw your way. Go up and down one rock, and then you have another huge roller to throw your bike up 10 feet in front of you. After making its way through endless rollers, the trail begins its descent back to the Cardiac/Ditch Trail. This descent is steep and technical—don't be afraid to use your brakes!