Hidden board park:
Go to name entry screen at career mode. Enter EVRSPRK as a name to unlock a hidden course.

Bonus characters:
Complete the various challenges to unlock Tara, Nate, Replay, Max and more bonus characters. Successfully complete all hard downhill gates to unlock Le'Monjello, Burg, Tex, and Gray.

Bonus event:
Successfully complete all events to unlock the Triple Crown Event.