Enter the following codes at the 'Cheats' screen:

Block party:
R, Y, Black, White

Power game:
White, Y, Black, Y

Easy steals:
R, X, X, X, R, Black, Y, White

Black ball:
White, White, Y, Black

Court select ball:
Y, X, Y, L, Y, X, X

Brick City outfits:
R, Black, R, L, Y, X, R, L

Cowboy outfits:
Y, White, White, R

Elvis outfits:
Y, Black, White, Black, Black,White, L, Black

Santa outfits:
White, Black, White, Black

Thanks to Revolution readers Tony Coburn and john!