Pirate's hat:
After the mini-boss on the first stage of the first level destroy Hairy Nanny Daycare.

Change Color in PDA games:
You can change your color with L and R while you're blinking.

Blonde wig:
Beat the game on hard.

Two-player hat codes:
Go to the Player Name Option screen and enter the following. Only for use in two-player mode.

Thanks to Revolution readers A Person, Shaw, and reckoning!