Sunday is the Dam to Dam FietsClassic. It is on the same day as a popular Dam to Dam run, so the cyclists can take advantage of the routes closed to cars, including the Ijtunnel!
I've signed up for the 65k route, a few friends are doing the 145k... I did a few "tours" in NYC a few years ago, including the Five Boro Tour (about 45 miles) so I know 65k is doable in a crowd and still fun. Also, the Five Boro tour ended in an hour of serious rain, so I should be ready with low expectations for Sunday. It's the Netherlands, it will rain.
I'm looking forward to it!