-squats
-stairmaster
-like Cream said, treadmill on an incline -- you can also use one of the ellipticals without arm things that does an incline
Hm, I should follow my own advice because I have no ass.
__________________
A hiney bird is a bird that flies in perfectly executed, concentric circles until it eventually flies up its own behind and poof! disappears forever....
-Ken Harrelson