How many persons do most of male "The Simpson" voices?
2!
Seriously! 2 of the voice actors on Conan O Brien. And I'm amazed; they have so much talent. It's a hilarious/fun clip. Enjoy!
http://www.muchosucko.com/video-simpsonsvoices.html (The link takes a while to load. If it fails, try again. The site has A LOT of hits per day so be patient.) :D