To use the phone booths you have to have a phone card. Buy the phone cards at the train station.
Holland has fisherman clubs made up of old men who go fishing together on the canals.
Street organ can be found on most pedestrian-only streets.
There are lots and lots of Pannenkoeken Houses here which have giant, flat pancakes that come on homungous plates. Often the plates are delftware which is a type of famous blue and white ceramic that has pictures of the Netherlands on them.
In Leiden you can find lots of quotes and poems written in different languages on the walls.
A hint about TV: even if you have cable, you have to get something else to get Cartoon Network. Beware!
Holland uses a different voltage, so you should make sure to get a European adapter.