Boston's Best Fringe Musical of 2011 is reopening  at OBERON--just in time for summer fare hikes.  "T" chronicles the journey of three 20-somethings whose lives have been derailed by the MBTA's shortcomings. When they discover a secret map that will enable them to conquer the evil of the T, they set forth on a colorful journey that is part love story, part melodrama, part scavenger hunt, mostly underground.  The show, now in two acts, includes new songs and material, as well as old favorites like "The Shuttle Bus Song (We Can't Handle It)," "The T Within" and "The Bro Song."