BMX Ultimate Combo
First, go to Beverly Hills. Pick up a BMX and head over to where the red ropes are. While on the BMX, face traffic. When you see a Jeep coming towards you, jump on it. It will stop immediately. While on the Jeep, jump up. You will be floating in mid-air. So, while in this position, pull off any trick for as long as you want. Any combination of tricks will work.
WARNING: If you use the LEFT Analog stick while in this glitch, you will fall and lose your combo.