DM's Esoteric Programming Languages
D. Morgan-Mar esoteric languages Chef, Haifu, Ook!, Piet, Whenever. Links.
Esoteric Non-existent Standards Institute
"Institute" for the standardization of unstandardized standardizable things, mostly esoteric languages and extensions to them.
esoteric.sange.fi
Collection of esoteric programming language implementations, examples, and related files.
Iota, Jot, Zot
Iota is unambiguous Turing complete language with only 2 symbols, heavily uses lambda calculus. Jot is Iota variant with elegant Goedel numbering. Also: 4 line Iota implementation,…
Malbolge: Programming from Hell
Specifically designed to be extremely difficult to program in.
Orthogonal
A programming language in which program flow can go sideways. Closely related to Befunge. Tutorial, reference, sample source code, Public Domain implementation available.
Programming in Malbolge
Introduction to Malbolge programming. Also propose modificatins of Malbolge for making programming in it more worse.
Shakespeare
A language with beautiful source code that resembled Shakespeare plays.