I hesitate posting this for folks who are really eager and inclined to believe it.
Then again, why should I put it off a few days/weeks until this thing builds on the rightwing internets and inevitably I get the e-mail forward with an anonymous "article" telling me all about how President Obama killed Andrew Breitbart because he "knew too much"? So let's just get it over with. Here you go, fresh meat for you Obama conspiracy nuts.
UPDATE (03.09.2012): This video, which has been around since at least 2008, is apparently the reason Obama was forced to assassinate Breitbart. Behold the scandalous truth that could bring down a presidency! (Courtesy of YouTube):
A bunch of people seem to believe there's a conspiracy behind Andrew Breitbart's death. The theory is that Breitbart had a video from Obama's college years that Obama didn't want released. So he had to die.
By Matt Stopera
March 1, 2012 | Buzzfeed