Notice the circular hotspot on the floor where the thing actually burned.
"So we're waiting for a flight in the United lounge at LAX, the flight next to ours was heading to London and in the middle of final boarding, when suddenly this guy comes running the wrong way up the jetway, pushing other boarding passengers out of the way, he quickly drops his laptop on the floor and the thing immediately flares up like a giant firework for about 15 seconds, then catches fire. About a hundred other people in the lounge jumped up and began a mix of gawking and general panic, I clearly heard a few fleeing individuals saying something about terrorists. The fire burned for a minute while everybody just stared at it, then another flare up, this one much larger than the first, drove a larger group of gawkers away. Eventually, the high intensity flaring calmed down and a larger fire kicked in, all the while letting off a thick cloud of white smoke that was slowly filling the terminal. Finally, an employee came over with a fire extinguisher and put it out of its misery.
I spoke to the laptop owner (while getting close for some pictures!) and he said he his laptop was an IBM, that he had checked the battery against the recalls on the net and his battery wasn't a recall. I don't remember seeing any IBM laptops nuke themselves yet on Gizmodo, just MacBooks and Dells with Sony batteries, but it was a close call nonetheless. If that thing had fired off while that plane was in the air, who knows what would have happened.
Also, we got to overhear some of the not-so-computer-literate people on our flight talking about how laptop batteries can explode if you "get too many viruses on your computer."