Graviboard by Conrad Kramer ($2.99)

Graviboard is a fun little tweak that lets you change the gravity of your Springboard. You can set it to equal Earths, the Moon, or zero gravity. Once you've configured it, you can turn your phone and the icons will all fall to whatever side is down and you can flick them around and watch them bounce off each other. Pressing the home button will disable the app and return the icons to their original positions.

This tweak is compatible with SBRotator, which is a plus! The screen is locked in portrait mode until the home button is pressed.

Here are the settings I use:

"Activation Method" Status Bar - Hold (Tap and hold on the status bar)
"Allow Launching Apps" Off
"Close on Home Button" On
"Include Dock" Off
"Show HUD" On
"Icon Settings" (left all default)
"Finger Mode" None
"Gravity" Moon

At $2.99, I'm not sure its entirely worth it. I do laugh a lot while tossing the icons into each other, though. I just think this add-on would be a lot more appealing in the $1-2 range.

Nevertheless, thank you Conrad Kramer!

Cydia Store Link (iDevice only):
Graviboard
More information:
Graviboard