SlapAMac lets you switch workspaces on your MacBook in a brutal way! This toy application runs in background and switches workspaces as you slap screen by left or right side. You can adjust sensitivity of sensor for better control.
Is it just me, or does this seem to slap things the wrong way? If I slap it on the left side, I would expect the slap to send it flying off to the right - but instead it slides left. This is on a first-gen MacBook Pro, if it makes any difference.