Bruges (Brugge) - Ride the canal boats (boottocht) around Bruges. One place to get the boats is G. Stael, Katelijnestraat. There's also a very nice park to run around next to the Begijnhof (Beguine convent) near the canal.

Go to the beach (Knokke-Heist, Oostend) - Belgian families go to the beach all year round. Even in bad weather, kids love a walk on the beach in the rain. Rent go-karts on the beach or shop for unusual shells. In Oostend, watch the big ferries coming in from England.