Was watching Ninja Dragon (
http://us.imdb.com/Title?0311584) today and came across a scene where a ninja hitman, having failed in his job is trapped in a corner by the intended target. The target starts to question him and to avoid spilling the beans he headbutt's the nearby rocky ground repeatedly and dies.
If anyone can come up with any more ridiculius/stupid/ingenious forms of movie suicide I'd like to hear them.