<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by DeltaMM:
I highly recommend Keukenhof Gardens. You're in luck--they open on March 21. Info here.
You can take a train from Centraal Station.</font>
I second this. Keukenhof is a great place to spend an afternoon (or even a day). It may be a little early in the season, but even if everything is not in full bloom, it's a nice place to walk around, and the greenhouses are fantastic. We'll be there the last weekend in March.