VIM BRAIN
An obscure little project that I finished recently was to create an esoteric programming language. My goal was to achieve the smallest possible set of vim-like instructions while being Turing-complete.
However, I am not the first one to try to do this. The first language to be Turing-complete with only 6 instructions was P′′ (P double prime) in 1964. Despite that, a variation from it created in 1993 got more popular.