Susan and I are going to Paris for a week in July, and taking Max (17) and Ben (11). We're looking for ideas of things to do there, especially unusual ideas that we won't find in the guide books. Ruins and climbing are the kinds of things the boys talk about when we ask them what they want to do. Already on our list are the catacombs and sewers. We might skip the Louvre entirely. Mont Saint-Michel is fascinating, but seems like a 3.5-hour trip there, so it's doable in a day, but it would be a really long day.