Plan 9, Inferno OS, and Hanna Montana Linux, as well a more interesting, but unique distro known as Hybryde Linux. Hybryde Linux was unique, in that your could switch between multiple desktop environments on the fly, so you didn't have to log out, then log back in to use them. It was weird in that as soon as it came out, they just stopped supporting it, making it one of those proof of concept distros that really left an impression, but never went far.
Of course there's also the mountains of religious themed distros out there. Most of which weren't very interesting, but there was Ubuntu Satanic Edition, which was just awful. It looked like something a 13 year would make well trying to be "edgy" and "dark." It used cliché titles like, "666 Edition," and filled the distro with stolen art and copyrighted music. Not to mention the awful the color pallet they used, which was a gross mix of black and red, again something a 13 year old would think is "dark" and "Satanic." All around, I am pretty sure the OS was made by a teen or someone trying way too hard to be "edgy."