Hi! I love this site and use it all the time, I teach a body sculpting class and I'm always in need of new material...please post any suggestions that you may have. Here is one I love. It's a little tricky at first but once you get the hang of it you'll love it....
To begin I lay a mat over my step and get one of the stability balls. Laying on your stomach, position the ball in between your butt and knees, on your hamstrings, using the heels of your feet to hold the ball in place. Begin by lifting your quads off of the bench. I do this 8 times, it's ok if you are barely lifting your legs you are still working those hams and gluts.
Next, position the ball on one hamstring right or left and lift this leg only, letting the other leg extend out, repeat on the other side.
You can add pulses at the end if you want...hope you enjoy.