Bird-Electron Keeperse Stainless Steel Cable Organizer
is a bit of a step up from Scotch tape. Just pop the cable into one of the felt-lined notches, and the weight of the whole contraption keeps those pesky cables from sliding back off the desk. A simple solution to an annoying problem: would that all difficulties could be solved this easily. Granted, for the $55 this is going to cost you, you could buy dozens of rolls of Scotch tape, but think of the aesthetics.