I realize this mainly concerns the Hague, but thought maybe enough people might be considering day trips from Amsterdam to The Hague to make this worth posting here too. I wasn't sure it would be as readily seen in any of the other forums.
Just a friendly warning that this event will be causing public transport and traffic disruptions in and around The Hague, and especially around the venue site of The World Forum. They are expecting demonstrations. There will likely be a fair amount of police presence.
For more information:
htm.nl (for public transport disruptions)