The reasons for success could change the way movies are made, marketed, and released. Story by Matt Cummings With January and February box office typically representing a rough couple of months for Hollywood, it comes as a surprise that 2015 has been one of the most robust in years. With receipts up 10% from the same period one year ago, theater owners are selling more popcorn and not having to shut down entire wings of their buildings due to the lack of traffic. The reason - or reasons - are simple: American Sniper and Fifty Shades of Grey . These two titans have pushed ticket sales and general admission numbers to points that we typically don't see until April - that's when tentpoles and more lucrative productions begin to arrive, ushering in the wave of Summer blockbusters. Sniper has made $307.7 million since its opening in January, while Grey became the biggest debut for a movie in February history when it bent over a four-day total of $93 million. B