the most obscure cds I own are releases from the band S/T
the album "music" is packaged in a movie box filled with popcorn.
it's nice ambien-psychedelic-krautrock
the album isn't hard to find or rare at all. even though it's limited to 67 pieces AND awesome, it's still available, because no one knows the band.
they also released a cd single, packaged in a 7" box, with plastic grass and plastic dogshit