Ride there :) I did last week. Was frickin freezing, but the North Sea Cycle route from hook of holland to near amsterdam is pretty amazing.
I rode London to Harwich and then the over night ferry to hook of holland. Then 60 miles up the LF1b and LF20 cycle routes.
Oh yeh, dam. Err theres there Anne Frank house and the Van Gogh musuem. Oh and the Heineken Experience is actually supposed to be quite good but i missed it as I was too stoned :(