Skate boarding
Hailed as one of the more dangerous sports, many parents keep their sons and daughters away from skate boarding. In truth skate boarding is about as dangerous as roller blading or bicycling. Any boarder will be safer if they are using proper gear, know the basics of skating, and know how to survive a fall.
There are several skateboard producers. Some are expensive and some are inexpensive. I would never recommend someone go to a discount store for any sport or safety equipment. They generally are not well made, and cause more harm than good. Skateboards can be expensive, and most parents don't like spending a lot of money when they aren't sure whether their children will stick with something or not. However, when it comes to cheap equipment you are bargaining with a child's safety.
Skateboards have three basic parts. The "deck" is the bandaid-shaped piece of wood. Generally there will be a gripping surface on part of the board. Do not expect this to be sufficient. Always make sure your children have on shoes with non-slip soles. Decks are usually 30-36" long, and shorter is better for the beginning skater.
The "trucks" are the (hopefully) metal pieces that attach the deck to the wheels. Wide trucks are the best for beginners, because they offer the best balance.
The third part of a skateboard is the most obvious. The wheels. Wide wheels offer the most traction, and should be on any board for beginners.