When you are playing tag or are in practice mode and you fall, press the TAB key and you will get right back up.
Enter the Baja race, go towards the outer walls. While gaining speed, lean back and keep going towards the wall. If you can get to the top go away from the cliff. You will be shot into the air like a cannonball. You will sound like one too.
When you hit a ramp press [print screen] a couple times, when you land you will get a huge amount of points.
Note: This code only works in the retail version