According to Medievalists.net, you can buy a 11th century castle in the old region of Gascony. It looks nice on the outside, and has walls 3 feet thick, so it would probably be quite comfortable in the summer. Unfortunately, it needs a lot of work, and doesn't seem to be too close to any major towns, though the countryside looks attractive, and the local town seems to get a lot of visitors during the summer, thanks to a local festival. But still. . . .if you're interested in the Middle Ages at all, maybe buying this old castle would be worth your money -- if, in these economically stagnant times, you happen to have any.