What's your best riddle/brain buster?

In this thread, just post your best riddles and stuff, make sure after four or five guesses you reveal the answer.

My Riddle (you've probably heard of it before): You're stuck in a building. There is 3 rooms that all have a door which you can escape from, one filled with murderers, one with fire and lava everywhere, and one with a lion that hasnt eaten in 7 months. What do you choose?

 

Busted : If there are three rooms in the building, in which room are you?

 

some center room, with nothing in it but three doors. each door leads to the thing stated above

 

Busted! The lion would die of starvation, murderes would kill themselves and the fire/lava room would just burn up!
The only choice now is room full of corpses/blood or a room with a dead lion...

 

well the dead lion part is correct,

 

I was going to post a really hard riddle, but the answer can just be googled.