Update 5:25 p.m.: The Associated Press report says the letters were sent to at least one other New York location aside from Viacom, and that the letters said there was a "10 percent change you have just been exposed to a lethal pathogen." Though initial tests showed them not to be lethal, the letter writer said he or she (or they) might send more that could be. Seems like an ill-advised plan... 

Original post: The FBI announced Tuesday that Viacom receiving "suspicious mailings" addressed to Stephen Colbert and Jon Stewart, and the Senate Sergeant at Arms Terrance Gainer reported that three Congressional offices also received suspicious packages containing powdery substances, but all the mailings appear to be harmless, Reuters reports.

The incident obviously recalls the Anthrax-laced letters sent to senators and news organizations in 2001, and Gainer treated it as an opportunity to remind staffers to be vigilant. It's also a reminder of the funny media climate we live in now when two Comedy Central stars could be lumped in as targets alongside U.S. congressmen in what appears to be a related incident. But of course, Stewart and especially Colbert are far more than comedians at this point, though just what it is that makes them (aside from children's book authors) isn't always clear.