Previously, it was only the Russians who were saying that the asteroid Apophis could smash into the Earth in 2036, but now a NASA spokesperson is admitting it's a possibility... albeit a slim one.
Everybody agrees that Apophis will swing by Earth in 2029 — coming closer than some of our geosynchronous satellites — but the Russian Space Federation believes that it may go through a gravitational "keyhole" that will bring it back around to hit Earth in 2036. (There are already a ton of websites, some of them religious, about the countdown to the 2036 apocalypse — just in case 2012 falls through.)
A NASA spokesperson, Donald Yeomans, insists the chances are 1 in 250,000 of Apophis hitting Earth in 2036. Says Yeomans:
The situation is that in 2029, April 13, [Apophis] flies very close to the Earth, within five Earth radii, so that will be quite an event, but we've already ruled out the possibility of it hitting at that time... On the other hand, if it goes through what we call a keyhole during that close Earth approach … then it will indeed be perturbed just right so that it will come back and smack Earth on April 13, 2036.
The asteroid will come close to Earth in 2012 and 2013, giving scientists a chance to fine-tune their predictions. (Update: As various commenters are pointing out, the indispensible Phil Plait has been busy debunking the Apophis story, including the idea that the 250-meter asteroid would actually destroy Earth if it hit us.)
The former Goa'uld System Lord defeated time and again by SG-1 may be coming back for revenge in 2036. Not the actual System Lord, of course, but the asteroid named for the fictional character Apophis (by the Stargate fan who discovered it).
There's a bit of poetic justice in the world being smashed by a Stargate villain — it could just be long-delayed payback for the cancellation of Stargate Universe.