Rotten

made by Michael Arntzenius, submitted by nicholasbs
A tiny Lisp designed for exploring the ideas behind Ken Thompson's Reflections on Trusting Trust: http://www3.cs.stonybrook.edu/~cse509/p761-thompson.pdf

datafun

made by Michael Arntzenius, submitted by porterjamesj
A research programming language attempting to generalize datalog. You can see the code here: https://github.com/rntz/datafun