First up, John Hodgman (the guy who plays "PC" on those Apple commercials), with an attack ad on his best friend and touring partner, Jonathan Coulton. I have read so many political ads worded just this way...I couldn't resist sharing it. It's excerpted from The Sound of Young America, an excellent weekly podcast hosted by Jesse Thorn ("America's Radio Sweetheart"). Visit the podcast site at MaximumFun.org (and subscribe!).
This is a very funny recording of William Shatner in a voiceover session, and his interaction with the producer of the spot. Funny...and a little familiar.
Also, I thought you might enjoy a few of funny and interesting video bits, featuring the current "king" of voiceovers, Don LaFontaine, and a few other major players in the industry:
Don LaFontaine: The Voice
5 Men in a Limo
GEICO spot
Good Morning: Don LaFontaine
Trailer, "Comedian"
Entertainment Tonight: Primetime Voices
Million Dollar Voices
Pablo Francisco does Don LaFontaine
Reenactment of a famous Orson Welles voiceover session