Toilet Lid Guitar

This is perfect for a crappy guitar player.

Matchstick Guitar

Amazing Guitar made from just Matchsticks.

Lego Guitar

Awesome guitar constructed entirely out of Lego pieces. The guitar is playable but had to be re-tuned after a few chops. The 'truss rod' he made for the back was not sturdy enough to handle the string tension for long which is why there are no strings in the pics.
Source: geekasaurus.com/clint/gallery/legoguitar

The Angel Sword guitar

Crazy guitar's

Interesting guitar's