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.
From the main menu, go to the options menu and select Cheat Codes. Enter the cheats exactly as spelled. After entering the cheat codes, toggle the cheats from the Game Options menu during gameplay.
Enter this code on the cheat code screen in the options menu-