First off-- I didn't see it firsthand, but a friend of mine just told me that in the most recent episode (#5) of "John From Cincinnati" on HBO, there's a street scene and in the background there are a couple 9/11 Truthers holding "Investigate 9/11" signs! Has anybody seen this episode, and/or the scene she's talking about?? My friend is not a truther, so the fact that they were prominent enough in the scene to come to her attention was what got me.

Here's the official site:
http://www.hbo.com/johnfromcincinnati/

And here are some mentions of it in the show's forum:
http://boards.hbo.com/thread.jspa?forumID=700004996&threadID=700011554&messageID=700625203#700625203
"Lots of placed symbols including "Investigate 911, Jesus, and an odd symbol on a guy's baseball cap."

http://boards.hbo.com/thread.jspa?forumID=700004996&threadID=700011554&messageID=700628228#700628228
"...during the crowd scenes in this episode, someone was holding a sign reading "Investigate 9/11." Probably someone from the Bill Maher forum."

http://boards.hbo.com/thread.jspa?forumID=700004996&threadID=700011554&messageID=700626505#700626505