Rihanna, supremely wealthy businesswoman and pop star, is going big for her 32nd birthday. E! got details about the party Rihanna had last night during her birthday getaway in Mexico, because of course RiRi had the fête abroad in some place warm: Why freeze in New York City or London when you can dance in the heat with mariachis?It was a grand ol' time, a source told the outlet, and it's not over yet.