Simple Brainf*ck, Ook!, Deadfish, and Befunge-93 interpreters written in JavaScript.
Brainf*ck / Ook! observes most of the suggestions from The Epistle to the Implementors. to create a better experience.
Deadfish is completely awful, I think my interpretation captures that.
As for Befunge, it is a beautiful language, but my interpreter is pretty crappy. Purely an academic exercise. Enjoy! (sarcasm)