It's simple, really: A length of bendable, grippy-coated wire is mounted to your wall. It can be turned, bent and shaped (as a "clip" or a "hook") to hold anything from a Nunchuck to a Rock Band guitar (and as a bonus, you won't ever have to separate the nunchuck or take the silicon sleeve off):
For $9.95, you'll get four clips in one of 10 colors: translucent, white, black, red, yellow, orange, gray, green, blue or purple.
It's a great solution for easily-accesible-but-organized controllers in a kid's room or a media den. But if you prefer to keep your gaming peripherals camouflaged, Wall clips work just as well hanging on the inside of a cabinet door.