Concept Art and Test Animations

Go to the main menu. Hold "C" and "Z" on the Nunchuk and pound this in on your Wiimote's D-pad (Directional pad):
Up, right, down, left, left, down, right, up.

9,999 Gopher Bucks

For 9,999 gopher bucks, hold "C" and "Z" on your Nunchuk during a game and press these buttons on the Wiimote's D-pad:
Down, down, left, left, left, left, up, left.

Unlock Antics (mini-games)

Go to the main menu. Hold "C" and "Z" on your Nunchuk (Again). Press these buttons on the Wiimote's D-pad:
Up, left, down, right, right, down, left, up.

All knapsack items

For all Knapsack items and flower power, hold "C" and "Z" on the Nunchuk during a game. Press these buttons on the Wiimote's D-pad:
Down, down, up, right, left, left, right, up.