I get it, Magic Trackpad. You don't want any gaudy cords messing up the smooth lines of your industrial design. But some of us prefer USB power over batteries—and we will not be denied.
This simple, non-invasive hack requires only a wooden dowel (approximately Magic Trackpad battery-circumferenced) with a screw in each end, a USB cord, and some spare wire. Remove your Trackpad batteries, strip the USB cord—carefully—down to red and black wires, and attached them to the corresponding poles of the adaptor. Like so:
And there you have it! It may not be as pretty, but it's way more efficient and green—assuming that the Magic Trackpad doesn't mind the 5V of USB power instead of the 3V two AA batteries will give you.
Assuming it does—and so far, there aren't any indications this has been a problem—the hack will also save you from having to buy one of those $30 battery chargers that are probably just Sanyos anyway. Magic! [MacRumors Forums via Hack A Day]