The advantage of having remote control is avoiding wires. This gives some freedom to place devices anywhere around. Traditional remote control requires a transmitter device which isn’t very handy is some situations – you have to find it first… what about having a remote where you don’t need a transmitter. There you have many options like clap, voice activated and other you can think of.
Befin made a whistle activated controller. He used an Attiny2313 microcontroller with microphone attached to it. Then he hooked RF remote outlets to it to be able switching various devices in a house. This wouldn’t be that simple without using a PC. AVR microcontroller has a V-USB running that allows connecting it to PC running Linux. This is where magic happens. Once MCU captures sound data FFT algorithm running on PC analyzes spectrum and decides weather there was a whistle or other noise. This is a quick hack giving the concept. This can be pushed further where you could detect whistle patterns for controlling multiple devices and even more.