Friday's the big day! The Expo Line extension officially opens at noon, and free rides start then and continue to the end of service tomorrow. (According to the schedule, the last Saturday night train is actually an early Sunday morning train.) But before all that, it had a grand opening this morning and, thanks to modern technology, we can live vicariously through the folks who were lucky enough to be invited to take that ride. Really soon, we'll all be able to enjoy a 50-minute ride from Seventh/Metro Center station in Downtown Los Angeles to downtown Santa Monica, just a few blocks from the beach.