I picked up a quick freelance job to do this physics simulation for a company that makes digital textbooks for high-school students. The idea was to create a Flash app that simulates kinetic energy, where you drop acrobats onto a trampoline to see how far you can launch an acrobat into the air.
I had to make sure the scale was correct, so the rate of the acrobat's fall corresponded to real-world physics in m/s (meters per second). The height scale was meters, so the art had to take some liberties (unless all our acrobats are enormous 20-foot tall monsters), but overall the simulation came out looking great. The artist did a wonderful job with the graphics, although as usual it required a fair amount of tweaking and modification on my part to get it working.