Enter any of these combinations on the race qualify screen (the one where 
you choose between race and qualify and practice).
LEGEND: U=UP, D=DOWN, R=RIGHT, L=LEFT T=TRIANGLE, 
S=SQUARE,C=CIRCLE, X+ X

Buggy Mode-
Hold Select and tap quickly R,U,S T (U SHOULD ACTIVIATED)

Bike Mode-
Hold select and tap d,u,c,t,r,u,s,t

Lava Mode-
Hold select and tap s,c,u,r,r,c,x

Gibberish mode-
Hold Select and tap l,t,c,u,d,d,r,c,s,s

Bonus Track-
Hold select and tap l,c,c,t,t,c,u,r (now go to course select and pick the 
new track)