Meet the kid who made 'wimpy' cool, in a family comedy based on the best-selling illustrated novel 'Diary of a Wimpy Kid' by Jeff Kinney, the first in a series that has thus far sold 24 million copies. 'Diary of a Wimpy Kid' chronicles the adventures of middle school student Greg Heffley, who must somehow survive the scariest time of anyone's life: middle school. Rated PG.