Hi - We will be in Leuven, Belgium for three weeks in August - three adults, one 4-year-old girl. We're spending three nights druing the trip in London (via Eurostar), two in Amsterdam. I'd love suggestions for family and kid friendly activities, restaurants, and so forth. We have all our lodgings for the trip.

The Zoo in Planckendael (near Mechelen). It's not a very big zoo but it's very natural with lots of green. (1/2 hour by train from Leuven)

A day at the beach.

I'll try to come up with more ideas later ...

Will you have a car? That will make a big difference in recommendations.
Even a 4 yo could enjoy Brugge, especially if you go for a carriage ride (unless your child is afraid of horses). Myriam, there's a Six Flags Belgium now, isn't there? I don't know anything about it though. And isn't there something called Plopsaland?

I'm not a fan of amusement parks myself, that's why I didn't suggest any. But Plopsaland might be a good idea as it's specially designed for very young children. It's in Adinkere, close to the sea. See www.plopsaland.be (only in Dutch and French)
No idea about Six Flags.

Hi - We will have a car, but if a train is easier, we'll do that. And no, she's not afraid of horses; quite the opposite!

There's also Mini-Europe in Brussels. All kinds of famous monuments from all over Europe in scaled size. Might be fun for the small one. There's also a few horse drawn carriages in Ghent.
If you're in Leuven from the 13th till the 15th, know that there's a huge city festival going on (www.marktrock.be). Might be exactly what you want... or what you want to avoid. On the main stage there are some excellent Belgian bands performing, top of the bill is Lou Reed this year. Kids never get bored of the beach, a boat trip in Brugge or Ghent can be nice too. The biggest zoo in Belgium is right next to the railway station in Antwerp.

I am just ending a month's stay in Leuven with 2 kids. Just outside of the city ring is Kessel-lo, with a very child friendly park and playground, but the wading pool is under renovation so you need to find other parks (like Zoet water or Bokrijk for water play. Bokrijk also has a historical village, probably more fun for older kids, but some terrific demonstrations and windmills; Mechelin has several good options (a short train or drive) including plankendael, technopolis science center and the toy museum. Brussels has a terrific children's museum and several parks as well. My kids liked chasing pigeons in the Grote Markt while the grownups had a drink at one of the cafes. There is also cafe behind the pubic library that is very child friendly. You can enjoy a cold drink while your four year old plays on one of the ride on cars in the enclosed square.
Have a terrific time!

Ok, I already KNOW I am going to get a lot of flack for this post ... but I will do it anyway. (I'm brave)

In London there is a (chain) restaurant called Rainforest Cafe (there is a few in the US, but not many) - No, it is not traditional English, but neither is McDonalds and I see plenty of people eating there!! Your 4 year old will LOVE it. The last time I went, I was sitting near the anomatronic gorillas. It was awesome. (Even I LOVED it and I am an adult - but then again I am a big kid at heart and always will be.) ... I thought the food was pretty good too. But if you don't want to go for a meal, at least go for dessert. Your little girl will thank you - and have a great time.

http://www.therainforestcafe.co.uk/