Those sneaky prepaid carriers Boost and Virgin Mobile are keeping a secret from us. We just received an invite for an event in New York City on Wednesday, August 22nd at 6:30pm that promises “big mobile news.” What is it? We’re not sure. Big would imply a tablet or phablet of sorts, but we’re wondering if maybe the two carriers will soon offer a prepaid version of the Galaxy S III. We’ll be there reporting live because they are promising soda and appetizers and, well, we like mobile news and food more than anyone else out there.