Possibly the best hamstring stretch in the world?
Use a machine like the DAP here or a doorway at home.
This has to be my favourite hamstring stretch. I like it for many reasons – firstly you can relax which is important for any stretch, secondly you are always very aware of your back shape (you have the constant feedback of the floor) and thirdly it is easy to control your hip/knee/foot alignment.
If anyone has thought of a better way of doing this, please let me know!