Krank Distortus Maximus is cool. Same idea as the Purple Plexi (i.e. blast the snot out of an LM386) but with a three-band Marshall style tone stack. I built one on perf and stuffed it in a box after a Ge/Si hybrid Fuzz Face. It's awesome because with the D.Max on lower gain settings, you can use it as a tone control for the FF, or you can mis-bias the FF and get some crazy ripping gated stuff, but then use the D.Max as gain recovery and compression so the "dying/sputtering out" sounds are more audible, or you can bypass the FF or run it cleaner and pull more distortion out of the D.Max, or select a smaller input cap on the FF and then dial the bass way up and the treble way back on the D.Max and get all kinds of weird rubbery sounds out of it...
Sorry I just wrote a novel. It's just amazing how much versatility there is in combining those two relatively simple circuits!
