A Bitcrusher is a digital audio effect, which produces a distortion by the reduction of the resolution or bandwidth of digital audio data. The resulting quantization noise may produce a ''warmer'' sound impression, or a harsh one, depending on the amount of reduction. Note : Bitcrusher exists in audio plugin (VST, AU...) too. Check here !
A fuzzbox (or fuzz box) is a type of effects pedal comprising an amplifier and a clipping circuit, which generates a distorted version of the input signal. As opposed to other distortion guitar effects pedals, a fuzzbox boosts and clips the signal sufficiently to turn a standard sine wave input into a waveform that is much closer to a square wave output.
Circuit bending is the creative short-circuiting of electronic devices such as low voltage, battery-powered guitar effects, children's toys and small digital synthesizers to create new musical or visual instruments and sound generators. So, do-it-yourself (or DIY) !
Oscillateur.com - Schematics, circuit bending f.a.q.