Gain some speed in a car and hold [Handbrake] until you have completed a full 180. 
Just before you complete the 180, release [Handbrake] and hold [Brake], which will 
spin you the next 180 degrees. Obviously you will end up facing the direction you 
were before the attempt. However, some vehicles cannot do this. Also with some 
vehicles holding [Brake] will spin you back the way you came while using the 
handbrake, resulting in back-to-back 180s.