plan an eight hour layover. Easy train straight from airport to den Haag, walk to the store, walk to the Mauritshuis museum with a stop for lunch, have a leisurely trip through the museum, take the local bus to the beach, take a nice long nap on the beach, bus back to the train station. My wife and I did exactly that from Amsterdam, were back in time for an early supper.
I'm not a big beach goer, or napper for that matter, but I do enjoy a nice walk through a foreign city; I'll never tire of seeing different cultures. I just have to find an excuse to travel through Amsterdam. My next trip is North Carolina to California, I wonder if I can manage a layover in Amsterdam.