I had bilateral hamstring damage from riding too hard one day in July that's still haunting me today, but MUCH milder, almost nonexistent. When I went to physical therapy, they introduced me to the foam roller and stretch straps. Using both of these have been super beneficial in recovery of extra rough rides like the one I had on Saturday.

Both of these tools can be had for about $23 on amazon

Foam roller 6"x12"
http://www.amazon.com/Black-High-Den...2507528&sr=8-3

Stretch Strap
http://www.amazon.com/Stretch-Out-St...bxgy_sg_text_b