I first saw one on an auction site and bought it and am now making them. Here's three I made. They have only three strings and are played with a "slide" or "bottleneck". The guitars have a great old time bluesy sound and are fantastic fun.
The History of CBG's :- Back in the USA late 1800's in the deep South among the black African Americans, money was too tight to buy instruments. The first primitive stringed instrument and a forerunner of the slide guitar was called a Diddley Bow. It was made from a piece of baling wire tacked across the wall of the wooden shack. You plucked it and changed the pitch by sliding something hard along it, like a knife, piece of bone or glass. Moving on from that some people attempted to make a crude guitar out of whatever they could find suitable. Before long the cigar box which was usually made from cedar, (actually a great wood for guitars) was incorporated with maybe an old broom handle for the neck and strung with some wire. Usually played with a slide too. Some notable people who started out on a CBG include Jimi Hendrix, Carl Perkins, Muddy Waters, Howlin Wolf. Early cartoons show Micky Mouse playing one!
"Smojo" is the trade name I have given my cigar box guitars. The old black American blues songs often mentioned mojos - a sort of good luck charm, so I have called my little enterprise "smojo guitars". The name being an amalgamation of smoking and mojo. Watch this site for much more about these incredible little instruments.