Cool link !
Since i found the answer to a1s' riddle, i'll submit one. Here it is :
A farmer walks with a very nasty dog, a goat and carries an enormous pumpkin. He comes to a deep chasm that can only be crossed by a narrow bridge. The farmer can only cross with one item (pumpkin, goat or dog) at a time. And he can't leave the dog with the goat (the dog would bite the goat) or the goat with the pumpkin (the goat would eat it). How will our poor farmer manage to get everything across and intact ?