The Purge grabbed the number one spot at the box office, and producer Jason Blum tweets plans for a sequel.The Purge was quite the hit this weekend at the box office, making around $36 million bucks. A huge number when you factor in that it only cost about $3 million to make. And the natural progression of movies like this is to pop out a sequel, especially when you consider that the Paranormal Activity franchise producer, Jason Blum, is behind the project. Well, get ready for another annual purge, because according to Jason Blum's company's twitter page, a sequel is definitely happening. Blum tweeted 'The Purge 2 is in development,' and a rep at Universal also confirmed the same news to Entertainment Weekly. The premise behind The Purge is that on one night a year, all crime is allowed in the United States. It's a government regulated 'survival of the fittest' approach to keep the crime rate down. The film stars Ethan Hawke and Lena Headey, as the parents of two children, who decide to keep their house on lock down during the annual Purge. And if you haven't seen the trailer yet, check it out in the description below to help fill in the blanks.This is an interesting film choice for Ethan Hawke, who most recently has stayed away from main-stream box office films. However, with the success of The Purge, as well as his new movie Before Midnight, (which, by the way, has received a ton of rave reviews since it debuted at Sundance) Ethan cou.