As per my last post the Heritage days are happening this weekend. This means that a series of houses and monuments which aren't usually open to the public can be visited (for free) this weekend. There are come queues but nothing massive. Most visitors are Dutch so don't be surprised if you have to ask for a tour in English which may or may not be available. So far I have seen:
With Ambtswoning (The Mayor's house) being my favourite.