Gowalla's mission is to inspire discovery by connecting people with the places around them. When Gowalla users virtually "check-in" at NASA-related venues via their iPhone, Blackberry, Android, Palm or iPad, they now have a chance to find one of the four items.
Virtual moon rocks can be found when Gowalla users check in to any location where a real one is on display. The United States successfully brought lunar samples back to Earth during the Apollo 11, 12, 14, 15, 16, and 17 missions. NASA provides a number of these moon rocks for display and public viewing at museums, planetariums and scientific expositions around the world.
To help people find the lunar samples, Gowalla and JESS3, a creative agency that specializes in data visualization, created a special edition NASA+Gowalla Map: Search for the Moon Rocks. Gowalla users can find the virtual NASA patch, spacesuit and space shuttles by checking in to NASA visitor centers, agency-related locations, or one of the more than 400 museums, science centers, planetariums, observatories, parks, nature centers, zoos and aquariums that are part of NASA's Museum Alliance.
For more details: http://www.nasa.gov/connect/gowalla.html