The HC-05, a Bluetooth to serial bridge, can be found for around $5 on the internet and therefore may be the cheapest way to add Bluetooth connectivity to your project. However, its default setting… ...

The Arduino interprets the SNES controller’s signals, sending them to his Android phone via a BlueSMiRF Bluetooth module.

On today’s edition of “really, really cool but ultimately not that useful” is a hack by Evan Kale to turn a PlayStation 2 controller into a wireless gamepad.