There have been some rumblings surrounding the next DLC for Fallout: New Vegas lately. Yesterday, No Mutants Allowed pointed to a small image Chris Avellone has been using as his twitter av that might well be from the game's next DLC. Then, a Bethesda forum user points out that next month's issue of Qore has a bit on a DLC for New Vegas entitled Old World Blues.
I got the newest issue of the Playstation Magazine, and a preview of next months "Qore" is always featured, next month's has information on Old World Blues. The next DLC expected was Honest Hearts, but we know Old World Blues is one of the titles Bethesda trademarked. Thanks to The Vault for the latter link.
The subtitle for it says, "Are you the scientist or the guinea pig?"
It's on page 6, and it releases on PSN on the 3rd of May.