The Doctor Demento Show is a two-hour-long syndicated radio program featuring comedy and unusual music. Dr. Demento was among the first to play Warren Zevon's "Werewolves of London", the first to play Weird Al Yankovic, and is pretty much the only way to hear "Fish Heads" on the radio.
Controversy Over Listings
Apparently Talonian Productions, the company which syndicates his show, refuses to divulge a list of radio stations which carry the show, to the extent that they will not even allow such a list to be posted on the Doctor's official web site. There appears to be a strong consensus that this is due to some variety of short-sighted self-interest on their part, but it is not at all clear how they benefit (even in the short term) from this policy.
2007-10-15 update: It appears that Talonian Productions is solely owned by Dr. Demento himself, and operated with the help of one or two staffers (as of c.2005), so any seemingly damaging practices they have may be simply the result of miscommunication or misinformation. Further research is needed to understand the situation properly.