Really cool bash one-liners by Nat Friedman

[jauco]

http://nat.org/blog/?p=825

[robertk]

Here's a fun simple one by yours truly (in Javascript so you can run it right now):

   javascript:(function(){s=x=' ';for($=_=1;$<1000;$+=_+=$)x+=_+s+$+s;alert(x)})()