Starting Memorial Day weekend, SEPTA will start offering deeply discounted roundtrip fares to/from Center City on Regional Rail trains on Saturdays, Sundays and major holidays. You can purchase these tickets online, in advance from a ticket office, and on-board trains at the same price. For more information, please visit the following location on the SEPTA website: http://www.septa.org/news/public_notices/weekend_round_trip.html