The real estate boom literally left Earth on Friday when - quietly, strangely - the BBC released some pointers about how to set up a moon base: first, look for "sites with a good supply of ilmenite... to extract oxygen, hydrogen and helium"; then "use lunar rocks as building supplies" because it's too expensive to bring bricks; and, finally, contact Dennis Hope, space estate extraordinaire. Mr. Hope "has sold lunar plots" to 3.4 million people, as well as some "Mars plots". Now in the works: "a private venture to establish a permanent, self-supporting community by the end of the decade." With images.