If you're curious about what an exploding laptop looks like, have we got a YouTube video for you. Since actually being on hand with a video camera at the exact moment a laptop battery decides to flame out is a one-in-a-million shot, the guys over at PCPitStop decided to deliberately overload a Li-ON battery pack to see what would happen.
The first cell blows out in a puff of smoke, blowing a hole in the wrist rest of this generic laptop. It takes a bit longer for the actual flames to break out, but once they do, it's like a fireworks display.
Naturally, this is a controlled demonstration and shouldn't be attempted by any amateur videographers out there. Our favorite part--after the smoke starts pouring out, the video's narrator calmly advises, "If this were a real-life situation, the best strategy would be to move away from the laptop quickly."