MotoGP 2
Floating bike mode
Edit the logo on a custom bike to read "kingpin".
Legends Mode
Unlock Challenges 62 through 66. Challenge 67 will be legends mode.
Mini-Games
To unlock some mini-games (the ones from Moto GP and a couple others), go into options menu and watch the text (not video) credits. Scroll down until you get to the credits for the mini-games. When it appears onscreen, press A. To confirm correct code entry, the screen with the "Mini Games" title will have the "A" in "Games" change to resemble that found that controller button.
Mug Shots Hint
When you are in the basement on Sheriden you will be able to see some mug shots on the right wall.
Play as Alex Barros
Get 250,000 points in stunt mode to unlock Alex Barros.