I saw this (pic, see it!) on the internets (on Reddit infact) yesterday. My first reaction was - it's not possible. It's just not. It had to be glued or something.
But curiosity happens. I spent an hour with a paper and pencil trying to work out the physics behind it. At 6 AM, i had finally constructed my own version of it (using only a stick and my pocket-knife). Here it is:
Doesn't it seem impossible? The rod sticks out with no apparent support to hold it up! The only torque is downwards! How is it staying there? But there is no glue or anything. It is simply mechanics.