Mac OS X 10.4.3 introduced a change in the Sudden Motion Sensor
The latest release Bubblegym version 0.4.0 does no longer work. If you are running Mac OS X 10.4.3 (or later) you should try version 1.0. Please report feedback to feedback(at)balooba.se and please include information about your hardware. Let us also know if your tilting feeds reversed.
Note: There appears to be an issue with certain PowerBooks (and possibly iBooks) that causes the Sudden Motion Sensor to not show up in Apple System Profiler. There is a discussion thread about this over at Apple's Support Forum (requires registration). At least one person has reported that Bubblegym did not work on his PowerBook and his system suffered from this SMS issue. This text will be updated when more info is available. If you know more, please mail us at bubblegym(at)balooba.se .