Bowling U.S.A. Codes -

300 game:
Begin game play, then press [F3] to display the practice menu. Remove all pins, then resume the game. Intentionally throw gutter balls in each frame to have the game score them as strikes.

Throw ball over gutter:
Either clear all the pins or leave some. Roll a gutter ball. While the ball is still in the gutter, right click and click "Practice Menu", then "OK". Then, throw a gutter ball and it will go over the gutter.