DIYer Warrior_Rocker wanted to make his classic SNES controller wireless, so he decided to hack in a USB Logitech receiver and transmitter so the controller could work with modern devices.
To hack this together, Warrior_Rocker used an old Logitech keyboard and receiver, a SNES controller and a few random bits. After disassembling everything, the wireless capability of the Logitech keyboard was transferred over to the controller, and then the whole thing was sealed up nicely with a battery. The final result is a classic SNES controller with wireless capability, and it looks fantastic. Head over to XodusTech for the guide to doing this for yourself.
Wireless SNES Controller Documentation [Xodus Tech via Hack a Day]