The Nvidia Optimus seamlessly switches between GPUs based on need. And based on this fellow being able to yank out a GPU while the rest of a system is running, it works rather well too.

Sure, it would've been funny if something had gone wrong at that 1:40 mark, but the fact that this little demonstration worked just the way it should is great news. By switching between integrated and discrete graphics, Optimus could one day double our laptop batteries' lives. And that's more exciting than any bit of sparks and smoke could've been. [nTersect Blog]