Real Programmers Code In Binary
Inspired by a cafe discussion of how pinball machines work, ZeroOne (or 'ZO' to its friends) is an editor where the only keys required are Zero and One.
If you press any other key, your document is wiped.
Using just Zero and One you can type the complete works of shakespeare, if you had enough free time.
Described at http://secretGeek.net/zo_intro.asp and available from http://zo.codeplex.com