dhenry:
Exploding caps can easily take out an eye or two.
I've got a couple of 68000uF caps on the shelf. They look at least 20 years old, maybe more. We used to hold a couple of wires on them to charge them up then melt nails across the screw terminals on the top. Stuff like that. Here's one of them with a couple of normal size components for comparison.
One day a little 10uF electrolytic exploded quite close to me. The metal case flew across the room fast enough to flatten itself against the opposite wall (which means it must have been going about the speed of a bullet...)
Ever since then I've been too scared to charge the big one.