Nicktoons Racing Cheats
Win all the races under the easy difficulty setting to unlock Mystery Rider.
Hold [Up] when the pre-race timer reaches "3".
Relay race turbo
When playing in a relay race, bump into your next person. That person will get a turbo burst.
Bonus characters 2
After finishing the game three times you will unlock Phil and Lil from "Rugrats", Sid from "Hey Arnold!", Doug from "Doug", and Otto from "Rocket Power".
Plankton and bonus track
After finishing the game once you will unlock Plankton and a bonus track.