Gahhhrrrlic:
Was that a random accident or were you doing something incorrectly with the battery at the time?
I was never really sure, there was no 'evidence' left.
However something went wrong with the charging causing it to continue to accept current, presuambly beyond the point of full charge.
If you hang around here long enough you will see many people assuming you can treat Lithium batteries like NiCd or Nimh, not worry about letting them go flat, assuming the so called 'protected' cells are inherently safe, use a hookey charging method etc etc.
Most of the time you might get away with it, but every now and again you wont, as indeed Samsung discovered recently.
I did once try to destroy a NiCd by putting masses of current into it; it did get hot and eventually stopped working with very dissapointing and very quiet 'fizz'.