I don't know about you, but I love a good exploding head. Ever since I saw psychic mutant head-exploder flick Scanners as a tot, I've tracked all the ways a head can explode in film. Sometimes it just pops like a watermelon dropped off a roof; sometimes it gets all bulgy and eye-poppy; and sometimes it goes slowly, with gradual brain leakage. Of course, science fiction is the perfect vehicle for the exploding head. And here's why.