You have to see this video.
It’s an AMD Duron CPU, overclocked to ~4GHz. When they remove the heatsink, the chip EXPLODES within about a second, blowing a HOLE through the motherboard and the table it’s sitting on, straight through to the floor.
Good thing Intel chips don’t do this, and know how to shut themselves down safely! I’ve known for a while that AMD chips will burn up within seconds of removing the heat sink, but I’ve never seen one blow up before…
EDIT: In the interest of fairness, a commenter on my internal blog pointed out this video of a supposed Pentium 4 doing more or less the same thing. With smoke.