If you realy don't have any time to visit anything there is only one attraction we would like to recomment.

It's Madurodam in Den Haag (The Hague). All buildings of some importance in the Netherlands are copied there on a small scale. If you erase "the others" in photoshop you can brag for years about all the sites you've visited.

You can probably even find a friendly Asian tourist who is willing to take your picture with Hansje Brinker at the entrance, or when you're standing in big clogs. Spend an evening at home looking up Hansje at the internet.

If you have more time, you can even visit the Hans Brinker Museum in Alkmaar.