NASA Space Apps ChallengeNASA is inviting all citizens of planet Earth to take part in a two-day coding marathon. The International Space Apps Challenge is meant to develop software for different purposes that support NASA's mission. It's open to just about anyone interested, including "engineers, technologists, scientists, designers, artists, educators, students, and entrepreneurs." The challenge will take place in several cities around the globe, including San Francisco, Santo Domingo, Sao Paulo, Nairobi, Tokyo and even on Antarctica at McMurdo Station. There are several challenges being put forth on the Challenge's website, including developing hand-held hardware for upcoming space missions, determining the size of the Earth itself, access to a variety of NASA datasets and observations, and designing a consistent open data API. Other challenges will be added as we get closer to launch time. As an example, the Earth measurement app must accomplish several things. For example, how to take a noon-time solar location fix, share that observation with others and demonstrate how far off the Greek astronomer Eratosthenes was in his measurement thousands of years ago. The event is being held partly to demonstrate NASA's efforts towards open government initiatives, as well as to capture the attention of people who may not have previously had any interest in space exploration.