This is my build of the Little Gem battery powered guitar amplifier, which I've housed in a cigar box. This circuit was also feature in Make 09 as the "$5.00 Cracker Box Amp". Mine cost considerably more, but I went through a lot of trial and error. This build is still a work in progress (note the lack of speaker grill and mismatched knobs).
It achieves a great, rich distortion and has decent volume for its size; however, I'm having trouble getting a clean sound out of it - even with the gain all the way down, the sound still breaks up (especially the low notes). I may try downgrading the 5k gain pot to 1k.