Skitching is when you grab onto something that's moving while riding so it can tow you down the road without you expending energy. My favorite is pickup trucks, but cars with spoilers, wheelwells or buses with large turn signals are also excelllent. Large trucks that seem to have desiel engines seem quite nice for skitching because they have to flip through lots of gears in order to accelerate so you don't get yanked around.

please note: skitching is dangerous/bad idea. One guy started yelling at me that his dad ran over his best friend while skitching.