I'm working on a POSIX-ish OS in Brainfuck.
I'm working on it because brainfuck is awesome and writing a kernel in it is even moar awesome. I'm currently trying to figure out how to port several basic GNU coreutils to the system.
The kernel boots and hangs in QEMU. That's good for now; at least it boots. Now, the important thing is actually getting it to run bash, and a few basic coreutils, specifically cat, mkdir, echo, ls, and cd.
Once it's done, I'm pushing to github (commented extensively, of course ;)