Off topic, but somewhat relevant... This just happened to me.

1. http://en.wikipedia.org/wiki/Debian_Almquist_shell
2. http://en.wikipedia.org/wiki/Almquist_Shell
3. http://en.wikipedia.org/wiki/Minix
4. http://en.wikipedia.org/wiki/Tanenbaum-Torvalds_debate

The effect is well documented: http://xkcd.com/c214.html