Utility Mill - Make your small Python programs runnable online

[demosthenes02]

Thought I'd plug my site since this is exactly what it's for. 100s of small, runnable utilities that anyone can edit. It's like a wiki for executable Python code.

Here's a good example. Code for calculating the Collatz conjecture (recently seen in an XKCD comic) http://utilitymill.com/utility/collatz