Penn Jillette, of "Penn & Teller", hosts a daily radio show on "Free FM", and on Monday, February 27, 2007, his guests for the whole show were Matt Stone & Trey Parker.
You can go to Penn's official Show site here : http://www.pennradio.com
And more importantly, you can listen to Monday's show here : http://podcast.penn.freefm.com/penn/251794.mp3
Just one more week until Season 11 - - SWEET!!!