Last weekend I was at Hargen Sail festival 2009. Hargen Sail is a huge annual sports festival on a beach up near the city of Alkmaar. Unlike most locations I recommend as someone who relies on public transport and bicycle, getting to Hargen Beach without the help of an automobile is pretty complicated. But if you do happen to rent a car, make your way towards the picturesque town of Schoorl and from there you will easily find Hargen.
To give you a feeling of the beautiful beach atmosphere after a full day of ultimate frisbee, volleyball, and sailing, here's a short video clip:
