A modular, abstract LISP-esque text parser. Functions and types are specified in a completely separate module from the core parsing logic. You can plug in new functions/types or modify old ones easily without delving into the parser logic.
Download, run, and start typing in LISP-esque expressions! If you want to add your own user-defined functions, then add them to ListOfFunctions.cs. As long as the body of the function returns what you want it to return, then you should be able to call it properly from the LISP parser.