My son designed a pinewood derby car for a 'open class' race we had the other night. He did the basic design, but got some help from Kevin Cole (a mechanical engineer at BYU) and I to tighten it up. Then he set about building the and painting the body, and went over to Kevin's house to put on the starter.
Finally it was time to race. Everything worked as expected. It was incredibly cool to hear the hiss of the car as it hurtled down the track trailing a plume of particulate dry ice. The only problem was the hump in the track — the car went airborne at that point, and didn't touch the ground again for 10+ feet past the finish line.
During the race itself, the car cleared the 30 ft in about 1.2 seconds, which is to scale speed of about 340 mph. (My earlier estimates were a little bit off.)
I hope you enjoy the video as much as we enjoyed racing it.