We are traveling to in Sept. Prague and have a 6 hour layover in Brussels and would welcome any suggestions of things to see, do or a place to grab lunch near the airport. Thank you!
It's around twenty minutes by train to Gare Centrale. I think you will probably have enough time to have a quick look at the Grand Place at least. It's a spectacular sight. Other than that, many of the interesting bits in Brussels are very spread around, and you probably won't have time to see them.
You could take the city tour bus that leaves from Grand Place. Or the canal boat. The old city is very compact, but the major museums are up a hill, which won't leave much time for you to enjoy them. Or you could take a cab from the train station to the museums (there are three next to each other), including a newish one on Art Nouveau works.