I recently stumbled upon Kurt Cobain's Montage of Heck - a compilation mix that Cobain himself culled from his record collection and would give to friends. I'd never heard of such a thing and found this detailed description of the mix and it's fascinating. Here's the proper description:

"Montage Of Heck" is a collage that Kurt Cobain assembled with a 4-track cassette recorder around 1988. It features sounds from Kurt's extensive and bizarre record collection, manipulated recordings of the radio, elements of Nirvana demos, and sounds created or recorded by Cobain.

The tracklisting is as varied as you can image, from Frank Zappa to Queensryche to children's recordings to John Denver to William Shatner. It's all over the place and is a bit of a trying listen but it's a fascinating tidbit of musical history regardless. Go listen.