The Bay Area is hosting Super Bowl 50 with Levi's Stadium as the host site, and many of the events scheduled to take place in downtown San Francisco. In the roman numeral usage, this is Super Bowl L. According to the host committee, however, they want the game referenced to exclusively as Super Bowl 50, and not Super Bowl L.
“I think we’re at a point now with Super Bowl 50, it being recognized as 50, the NFL doing what it's doing around the celebration of 50, that it’s probably time to introduce the Arabic '50' as opposed to ‘L.’"
The NFL had a fairly brief response:
“No, we do not have a comment on our official plans for Super Bowl L.”
That would seem to indicate, it will remain Super Bowl L. We at Niners Nation will likely bounce back and forth between the two, and hopefully we're doing it a lot in January and February 2016.