William Wu's Riddles.

This is an oldie but a goodie: a large collection of logic puzzles, archived and arranged in order of difficulty by William Wu (since Spring of 2002).

For instance, take this one called the Cork, Bottle, and Coin (easy):

If you were to put a coin into an empty bottle and then insert a cork in the bottle's opening, how could you remove the coin without taking out the cork or breaking the bottle?

Link

The fantastically weird cork and bottle is the swedish dog decanter by Hugo Gehlin, from hi+lo modern glass