I just googled my site for Stair Dismount and I can't believe I never blogged it before! There is a new version called Truck Dismount which takes the premise of Stair Dismount (define a few variables, launch the dismount and see how much damage the body takes) but instead of stairs uses a moving truck and a few ramps! I really shouldn't be playing this at work, but it's terribly addictive. It has a good mix of complexity and ease of entry. The complexity is a time sink because you keep tweaking things trying to create bigger crashes and more damaging launches.