Discussions in the forums about detecting slope, combined with a recent show about Evel Knievel that I saw on the History Channel, prompted me to work on an Evel tribute.
The bike uses the color of its wheels to detect terrain and act accordingly. The scripts started out pretty complicated and ran rather slowly, but after some whittling down, it now works pretty well.
Lots of comments are included to help explain how the simulation works. In essence, the bike move the direction that it's pointed unless it isn't touching the ground. In this case to moves by the Vx and Vy that it was previously, and decreases Vy by the amount of "Gravity".
It would be possible to count how many times the bike was touching the ground to determine how hard it hit and cause a "crash". This would be pretty fun on a scrolling background, or in a project where you could draw your own "ramps".