The latest odd social gaming rumor comes from the film side of the blogosphere: Zynga is working on a film adaptation of its game Mafia Wars, with a studio called Radar Pictures, according to a Pajiba story that has been picked up by a number of other blogs, and is now spreading across Twitter.

We’ll save you any suspense; Zynga says the rumor is untrue. We’re waiting on an email response from Radar, but a representative we briefly spoke with on the phone could only say she’d “check on” the rumor, in a tone that didn’t suggest any familiarity with the idea.

The rumor brings up an interesting question, though. Namely, how long will it be until there really is a film based on a social game? Zynga’s response to us notes that they’re “approached all the time”. That much should be obvious from the company’s forays into brand partnerships, including the just-ended 7-Eleven in-store marketing push and a new Kia ad campaign.

And movies have been based on far less. The cinematic version of Prince of Persia, based on the PC and console game franchise of the same name, just earned heaps of money despite terrible reviews. Video games have become a cultural phenomenon, with social games like Mafia Wars and FarmVille achieving unprecedented audiences. Today’s rumor is untrue, but it was hardly an unreasonable idea.