Here are a couple of activities for families with kids staying in Brussels these holidays (also good for adults, but you can take the kids as an excuse to visit…):
Dinosaur gallery at the science and natural history museum in Brussels: An impressive collection of dinosaur skeletons, easy to navigate, informative and fun for kids and adults (and manageable for an afternoon, as it is not too large but still big enough to make the visit worthwhile). Check out the website for special workshops and activities for kids, such as the paleontology lab. (The museum is closed on Dec 24, 25, 31 and January 1st)
La Balade des Gnomes: A fairytale hotel in the Belgian countryside, ideal for a weekend getaway. Local activities in the area include hiking (maybe too cold for this time of year), skiing, an adventure activity park, and more, which you can read about on the website.
If you’re looking for the all-out version of a fantasy world and don’t mind a longer drive, consider a trip to Germany’s Phantasialand, which is hailed as one of the best amusement parks in Europe and maybe a better option for the winter. The park is in Bruehl, just outside of Cologne.