San Diego-based Eventful, the online website which helps consumers find live entertainment and local events, reported this morning that it has reached 20 million members on its site. The firm claimed that the milestone makes it the largest, aggregated audience for local entertainment seekers in the world. Eventful lists local events, concerts, music, movies, family activities, and more. Eventful is venture backed by Bay Partners, Draper Fisher Jurvetson, Omidyar Network, and Telefonica.