The temperatures are up there and it's hard to step outside without breaking a sweat. Summer's officially here, and dressing for the occasion isn't always easy. Even celebrities who try to tackle the season don't always look their best. Whether it's actors like Leonardo DiCaprio or some of today's hottest rappers, we put on our best professorial gear and see who made the grade so far. Sharpen your pencils, stand up straight, and get ready to learn. We're taking you to Summer School: Grading Celebrity Style.