ESPN X Games Skateboarding
Press Up(3), Down(3), Up, Down(3), L1, R1 at the title screen.
Big head mode:
Press Up(3), Down(3), Left, Right(3), L1, R1 at the title screen.
Alternately, Get 30 licenses in arcade mode with any character,
then press Square + X at the character selection screen.
Another arcade mode:
Get all 36 licenses in arcade mode, then press Circle at the
stage selection screen.
Hold R1, R2, L1, or L2 at the character selection screen.
To get secret boards, complete X Games with a gold five times
in a row. Repeat this to keep getting new boards.