interpreter for a concatenative language
Conca is similar to Joy and Cat. It is young but can already do quite a bit: it includes most of the basic functions and can read definitions from a file. Definitions are different: Joy : square == dup * Conca : [ dup * ] "square" define
The MDK provides a simulator of D. Knuth's MIX computer, and a development environment to write, run and debug MIXAL programs on it.
Wisp is a small Scheme-like language designed to be easily used in various structured data processing tools. The accent is on simplicity, automatical generatibility, and efficiency. (Currently on long hiatus. Gauche has similar goals and is maturer.)
drogue (dercz rogue) - occult roguelike game written in c. The Most Dangerous Game of Dercz Stanislaw.