A cool concept, and funny to play with, use google shell-style:

http://www.goosh.org/

After reading this post I tried out the code snippet of Jan but honestly my eyes did not like it. The yellow didn't look good to me and I also had the feeling that the smiley was a bit overkill.

But as I truly liked the Idea (thanks Jan) I changed it a bit to comfort me.

A screenshot: