Around Holland

Some nice activities a bit further out into the province, but all within 1 hours drive:
Aviodrome, a very nice airplane museum in Flevoland (a province developed entirely from reclaimed land)

Of course the world famous flowers are not to be missed in the springtime, for instance at the Keukenhof (30 mins drive)

Castles can be visited at the beautiful Kasteel Haarzuilen (30 mins) or Muiderslot (20 mins) 

For the kids: Sprookjeswonderland - fairy tales come alive. And a wonderful huge playground. Inexpensive, old-fashioned fun.

Next to sprookjeswonderland is the Zuiderzeemuseum, which offers a lifesize replica of everyday life in coastal Holland from a historical perspective.

Other typically Dutch outings include visits to fishing villages Monnikendam and Volendam, the windmills at Zaanse Schans or Kinderdijk, the lovely dairy farm Clara Maria (in Amstelveen), and so forth. Beyond Amsterdam, other interesting nearby cities worth visiting include Haarlem, Den Haag, or Rotterdam.