If you drive off the track in a piston cup race and press the Z button, it will put you back on the track a full second ahead of where you were. [by: up_up_and_away]
Enter in the cheat menu:
YAYCARS - All cars
IMSPEED - Fast start
VROOOOM - Infinite boost
TRGTEXC - Unlock Master's Speedy circiut and Master's Countdown cleanup
MATTL66 - Unlocks all tracks and mini games
IF900HP - Unlocks all tracks and mini games
R4MONE - Unlocks all paint jobs
CONC3PT - Unlocks art
WATCHIT - Unlocks movie clips
[by: krusty]