The first Cub Scouts to participate in a pinewood derby were from Cub Scout Pack 280c of Manhattan Beach, Calif. The event was originated by Cubmaster, Donald Murphy, and was first run in the Manhattan Beach Clubhouse on May 15, 1953. The event was later publicized in the October, 1954 issue of Boys' Life.
Since then, an estimated 40 million Scouts have participated in races. Millions more-parents, den leaders, Cubmasters, committee members-have been involved in various ways.
The rules of the very first race stated: The derby is run in heats-two to four cars starting by gravity from a standstill on a track and run down a ramp to a finish line unaided. The track is an inclined ramp with wood strips down the center to guide the cars.
Years later, the race is run the same way.
Each year Pack 229 hosts it's annual Pinewood Derby, typically in late January.
Official Pack 229 2009-2010 Pinewood Derby Rules
The car kits are all pre-cut, you do not need to modify the cars at all.
The two critical factors are weight and reduced friction. Try to get the weight of the car as close to 5 ounces as possible. (All weight must be added to the outside of the car) If you add weight to the bottom be sure to check the clearance height. Hint on the weight - coins work really well and weigh more than the store bought weights cost. Weights must be purchased separately.
To take care of the friction, polish the axles. Do this by inserting the axle nails into the chuck of a drill. Mount the drill in a vise and hold a strip of wet sand paper on the spinning nail. Also use plenty of powdered graphite on the axle before the race. I don't recommend using glue on the axles. Check out the following website for a tool, Pro-body Tool 2, that helps with drilling axel holes: http://www.winderby.com/m06_040829.html.
These are a couple of basic tips. Please don't over think this. The Cub Scout should be doing all of the work with just some help from help from parents.