Can you solve these riddles?

A "riddle" is a type of question which usually has a clever or funny answer, and that you often have to solve as a game.
I challenge you to solve these:

1) What has many keys but can't open any doors?
2) Can a kangaroo jump higher than the Empire State Building?
To find the answer click onto http://www.manythings.org/jokes/9966.html. You can even listen to them.