I've seen people do some evil stuff to them...trapping them and letting them starve, drowning them, burning them like a pyromaniac...
I also understand it's possible for them to get electrocuted, although I've never seen it. Also spontaneous combustion.
But I don't know, I just can't do it!
I'm a vegetarian!
It just seems sadistic to me, to take pleasure in killing these helpless little Sim people that you have godlike powers over. I know they're just pixels on the screen, but it's the idea of it, not the actual act. You just KNOW there's someone out there, like my JPD, who's playing with Sims and is thinking "I wish I could trap a REAL girl in my house and watch her suffer".
But, mind you, I don't think that should not be in the game or anything. It's a really good part of the simulation that it's possible for them to die, and it's not just a stupid happy little utopia, like Sim Town. And the thing that, in my mind, makes The Sims an UBER-great game is that it's totally open to whatever you want to do. Even if you want to do evil.
Wow, I wrote a lot on this!
(Matthew, don't think I've forgotten your killing of Avocado Man and his apartment building )