Perhaps this is not what you had in mind, but I would recommend a trip down to Utrecht. As near
as I can recall (I lived there about six years ago), it takes about 30 minutes by direct train from
AMS. Utrecht is a charming university town where you can take a canal ride, visit the Domplein
and take in a spot of lunch on the roof terrace at the V&D (Vroom & Dreesmann; connected to the
train station in the Hoog Catharijne shopping centre).
H