A basic ramp used when skateboarding to get air. It looks nearly exactly like the inclined plane in your old physics textbook, but with a little curve to it. A launch ramp, or just launch, can be anywhere from 1.5 to 4 feet (.5 to 1.3 meters) tall. They fell out of style in the early 90's when street skating became more popular, but made a small resurgence in the past couple years.