Retractable USB cable
An artifact courtesy of the not-as-useful-as-you-think-it-is department: a retractable USB cable. Space is certainly at a premium in every nerd’s backpack, but come on. The only time I think something like this would be useful is during some Mission Impossible style corporate espionage.
I can imagine someone gingerly feeding this cable through the ceiling, from behind the slats of an air duct, ready to snap it back at a moment’s notice. But what are you trying to do anyway? Charge the enemy’s BlackBerry?
Worse, because it has to coil around a plastic pulley, the cable is thin and unsettling. I couldn’t get rid of it fast enough.