And just when you thought the possibilities of a 20+ year old system had been exhausted, enter the GetLoFi Precision Oscillator.
The oscillator is one that plugs into a side port on the Famicom, and allows for extreme manipulations of the sound and picture. The parts and instructions can be yours for cheap, and all you have to do is build it.
Sometimes, the oscillator can induce an all-out spazz fest. And if all this circuit-bending stuff is a bit intimidating, it's....you know, for kids: