De Oerkap, Haarlem
Amsterdam has city beach + Roest and Haarlem has City Beach de Oerkap. The idea is pretty much the same: a mess at first glance, but actually a well-organized intention and the ideal place in the city for a sunny day (or Sunday or one of those days when you hoped it would be sunny). Plus: just like at Rust The gentlemen and ladies behind StadsStrand de Oerkap like to party and so live music sessions and other types of parties are regularly organized. Unlike in Amsterdam East, the Oerkap in Haarlem is not open all year round: they will be open again from April 1, 2016 and - of course - this will be conducted with a bang party. Buying tickets is recommended. City Beach de Oerkap.
image on the right via @haarlemcityblog