A very tiny concatenative stack-based programming language, based on MUSYS by Peter Grogono and Peter Zinovieff, "MOUSE" as described in Grogono's 1983 book "MOUSE: A Language for Microcomputers" and rebooted by David G. Simpson in 2002 -- hosted here, for all of eternity.
Mouse-2002, while a useful and extremely terse language, is incapable of computing ackermann(3, 10) in less than the age of the universe, doesn't know anything about strings, implements one continuous array, and overall does emobody the year it was designed -- 1979. This repository hosts a fixed and updated version of the Mouse-2002 interpreter found here.