1966: The one-hundredth soccer game between the Netherlands and Belgium. The Dutch won with 3-1.
1985: a media strike, which resulted in no tv and radio at all.
1987: Closing of the Philipsdam, and thus the completion of the
Delta Works. (a huge Dutch victory over the sea)
I like this one:
1986: the peace treaty between the Netherlands and the Scilly Islands, which ended
the 335-year war