I just got a new toy. This is a Fuzz Face pedal for guitar, bass, keyboard and whatever else you can think to run through it. I like this thing a lot. It's pressure sensitive too. The stronger you strum a note, the more the fuzz is activated, so you have a lot of control over the sound of your sound. I wonder if it's a coincidence it's called Fuzz Face and it looks like a smiling face.
There are distortion pedals, overdrive pedals and fuzz pedals. A fuzz pedal has a sloppy sputter sound whereas the overdrives are more warm and solid, and distortions are cutting and sharp. Youtube explains it a lot better than I can.
FUZZ (You may want to skip ahead to 2:30)