Application switcher for Mac that lets you switch between windows, not just applications. Very handy for those of us trying to avoid the mouse. Oodles of options.
If I used a screensaver… Reacts to sounds it hears through your Mac’s microphone. Only appeared on my PowerBook’s screen, not the external monitor, but still nice.
Mac OS X toolbar to-do list manager. For me to remember if I start using iCal’s to do list. (via plasticbag.org)