Scharpling and Wurster
Latest, greatest thing out there: Scharpling and Wurster. "The Best Show on WFMU" is a clever, random set of commentary and comedy bits hosted by Tom Scharpling, now (slightly) better known as a writer/producer of USA's Emmy-winning "Monk." He also did the voice for a psychotic onion-creature on Aqua Teen Hunger Force (all my favorite entertainment things are starting to tie together).
Jon Wurster, drummer for Chapel-Hill, NC favorites Superchunk, calls in to the show on a regular basis, performing a wide range of characters in a narrow range of voices. Wurster's calls always start with a strange premise executed matter-of-factly that devolves over about half an hour into a psychotic character who either threatens to kill Tom or himself (or both). Four stars!
The Best Show archives are at: http://www.wfmu.org/playlists/bs (You learn to pick out which descriptions apply to Wurster characters pretty quickly; former Dr. Katz star Jon Benjamin and other callers also contribute characters)
A list of characters is at http://www.friendsoftom.com
You can buy the first three compilations of their work at http://www.stereolaffs.com