Cub Scout derbies—the pinewood derby, raingutter regatta, and space derby—are optional but valuable activities for Cub Scouts. Many men who once were Cub Scouts fondly recall their derby experiences: planning the design of their vehicle, working with a parent to build it, and seeing it perform on race day when, win or lose, they could take pride in having done their best. In this way, the three basic lessons learned by participating in a Cub Scout derby—the craft skills, the rules of fair play, and good sportsmanship—are remembered for a lifetime.
The pinewood derby is one of the most popular and successful family activities in Cub Scouting. Pinewood derby cars are small wooden models that boys make with help from their families and then race in competition. The cars are powered by gravity and run down a regulation track. The pinewood derby is an annual event in most packs. It can be run indoors or outdoors. Every boy can design and build his own "grand prix" car to enter in the race.
The raingutter regatta, in which boats race along a narrow channel, has two versions. The wind-powered version uses sailboat designs, and the boats are blown down the channel. The propeller-powered version uses motorboats driven by propeller.
Another popular family-son project is the space derby. It's similar to the pinewood derby except the models are miniature rockets driven by propellers powered by rubber bands along a suspended, heavy monofilament line.
Each den works together to build a "Cubmobile," a pint-sized racing vehicle. Each den has one racer, and each boy in the den races in the car once. Usually, a ramp is used to help start the cars, and they are gravity-propelled downhill to the finish line. The race is held on a smooth street with a gradual slope, in cooperation with local authorities.