The project he refers to in the video clip below is titled The Apocalypse and already stars himself (James Franco), Seth Rogen, Jonah Hill, Aziz Ansari and Craig Robinson; each of them will be playing themselves in the movie. In it, while attending a party at James Franco's house, along with many other celebrities, the apocalypse begins.
It's scheduled to begin soon down in New Orleans on a $30 to $40 million budget with Sony Pictures distributing it.
I actually dig the idea; of course how good the film is will be all in the execution, with Seth Rogen making his directorial debut (co-directing alongside Evan Goldberg).
In the below clip, talking to MTV, Franco says that Rihanna (who'll be making her big screen debut in Battleship) has a part in the film.