Is this an event? We'd say so. We've only waited our whole lives for it. Here's some FAQ'a via the MBTA's official site
Beginning Friday night March 28, 2014, the MBTA is extending the hours of service by 90 minutes for Rapid Transit and Key Bus Routes on Friday and Saturday nights. The last Red/Orange/Green/Blue Line trains depart downtown stations approximately 1:00 AM on Sunday through Thursday nights, and approximately 2:30 AM on Friday and Saturday nights. Individual schedules for each station and route can vary; for example, the last Green Line and Red Line trains are scheduled to depart Park Street between 2:24 AM and 2:36 AM. This extended service will provide a transit alternative for many patrons and employees of late-night businesses, including those in the restaurant, entertainment, and hospitality sectors.
Q: What service will be operating until 2:30 AM Friday and Saturday nights?
A: Rapid Transit—the Red, Orange, Green, Blue, Mattapan and Silver Lines (except SL2)—and the Key Bus Routes. The Key Bus Routes are 1, 15, 22, 23, 28, 32, 39, 57, 66, 71, 73, 77, 111, and 116/117. THE RIDE paratransit service will also operate to areas within ¾ mile of all late night services.
Q: How were the services to have extended hours selected?
A: Rapid Transit and Key Bus Routes serve over 70% of all trips made on the MBTA each day. The map of the Rapid Transit and Key Bus Route network is already posted on most MBTA vehicles and in most stations, so this helps customers understand and take advantage of the new service.
Q: Will the extended service operate like other MBTA service?
A: Service will operate as it does during the day, serving the same stations and stops as the normal routes. Regular rapid transit and bus fares will be charged on late night services.
All new trips will be scheduled, and will appear on the MBTA website, on phone apps, on Google Transit, and anywhere else that such information is usually available. Real-time information for buses will also be available for the extended late night service. Real-time information for the Red, Blue, and Orange Lines, including the countdown signs in stations, may not work after 2:00 AM, due to current technical limitations.
Q: How frequently will service operate?
A: Extended late night service will operate approximately every 15-20 minutes in most cases. Some corridors served by multiple routes(such as SL4/SL5 and 116/117) will have combined service levels of every 15-20 minutes, or every 30-40 minutes on unique segments.
Q: Are there other routes or schedules affected by this change?
A: Bus trips that normally wait for “last trains”, which are generally identified by “w” notes on schedules, will no longer wait on Fridays or Saturdays if they do not have extended late night service. The last trips on these bus routes will instead depart at their scheduled time on Fridays and Saturdays. This affects Routes 9, 10, 11, 16, 24/27, 26, 31, 34, 35, 36, 43, 44, 47, 64, 69, 70, 72, 74, 75, 80, 83, 87, 88, 89, 93, 95, 96, 99, 106, 108, 109, 110, 120, 134, 210, 216, 426, 442, and 713.