Enter these codes as the player's name (press R at the Bike Selection screen). If done correctly you will hear a sound:
N64fergusFace on cycle rollerEveryone is a rock xtremeFast turbo antigravUpside down tracks magnifyMagnifies stealthYour bike is invisible fisheyeFisheye lens ghostlyTransparent track wiredWire frame version uglymodeSilly graphics arsenalWeapons when you need 'em bananaSuper-slippery tracks nitroidInfinite turbos Xgteam Face will be on your car (go back and enter a designers name ash, shawn).
At the Password screen, enter:
81GGD5 for access to all the bikes and tracks
61DDB5 for only the cars Neon and Roach
Thanks to Revolution readers Killerkid0, Blarkin007, Mitch Olsen, and Maximilien