Have you ever heard of polyglots? This is so crazy. A polyglot is a program which can be interpreted as many programming languages. You don't believe me that something crazy like that is possible? Here is an example I've made:
See public gist, as Jekyll keeps crashing with this.
You can download the file at martin-thoma.com/python/polyglot.py.
It might be considered as cheating to use comments as often as I did and using two esoteric programming languages. Whitespace works only with whitespaces (space, tab) and Brainfuck needs only +-.;<>. Everything else is interpreted as a comment.
When I have much more freetime and I don't know what to do, I'll probably write some code with a more interesting output and which is not that obvious.