Skateboard Wheelie is a fairly simple game that requires you to maintain a wheelie on your skateboard for as long as possible. Along your path, you'll find little silhouettes that you can try to fit into, but you're probably better off just doing your best to keep the wheelie going. Eventually you'll probably match a silhouette or two.
Frankly, this isn't one of the best games on the site. It's just barely worth publishing. Some people might like it, but most of you won't want to bother. It's better to play a cool game like Minesweeper or something that you enjoy instead.