'This Is The End' Trailer: Seth Rogen & Friends Party At The End Of The World (VIDEO)

According to the Mayan calendar, the world is supposed to end on Dec. 21. If that happens, audiences won't get to see "This Is The End," which is too bad since it looks really, really funny.

Some backstory: Previously called "Jay & Seth Vs. The Apocalypse" and "The End of the World," "This Is The End" started as a short film starring Seth Rogen and Jay Baruchel as versions of themselves dealing with the end of time. "This Is The End" expands on that premise, making Rogen, Baruchel, Jonah Hill, Craig Robinson, James Franco and Danny McBride survivors of the apocalypse, which strikes during a Hollywood party at Franco's place. (Sorry, Michael Cera and Jason Segel, both mentioned as fatalities in the clip.) More deaths likely follow, and judging from the very R-rated trailer above, they will be violent. Here's co-star Baruchel speaking to io9 back in January of 2010:

The one thing that I can say -- that was my pitch, my idea, that I think we'll end up doing, because it would be foolish not to -- I want a recurring joke, because it takes place in Los Angeles, and there's a lot of famous people in Los Angeles, I want a bunch of cameos, but I just want them to be corpses. I want them to be like, "Oh god there's Will Smith's dead body in the corner!" And it would actually be him. So that's my recurring joke for the movie: I want there to be a lot of dead famous people in it.

If celebrity carnage isn't what you find funny, "This Is The End" also features meta jokes about Rogen's acting and Franco's sexuality.

Watch the very R-rated "This Is The End" trailer above, with a special introduction from Rogen and Franco. The film was co-written and co-directed by Rogen and Evan Goldberg, his partner on "Superbad."