I found these on youtube. Sort of like Tenacious D, but with extreme metal. Check em' out. (The first 50 secs of the first vid are blank for some reason, but it's there.)
http://www.youtube.com/watch?v=RANzJX57ehM
http://www.youtube.com/watch?v=GKKgNWwRa4s
http://www.youtube.com/watch?v=RANzJX57ehM
http://www.youtube.com/watch?v=GKKgNWwRa4s