I wasn't even sure what this did at first; all I knew is that I wanted one. This heavy-duty knob is called the PowerMate, a volume knob and programmable controller for your computer. You can use it to edit home movies or scroll through long documents or create your next audio masterpiece. Since it’s an assignable controller, you can program it to do anything you want, in any application. Customize it. Program it to execute any key command, in any application. It even comes preset to work with iMovie, FinalCut Pro and GarageBand right out of the box.

$36 from Griffin, and also available at Amazon.