BostonTechMom has an informative post about the upcoming LexHack at Lexington High School, on September 19 from 8AM to 11PM.  LexHack is a free, student-organized, all-day session for high-school students of any level of programming ability throughout the Boston area to collaborate on software projects.  The day (and evening!) includes prizes, food, mentors, learning, teamwork, and achievement.  BostonTechMom reports that last year’s more-than-70 participants found that it’s a great way to learn a lot and meet new friends in a short amount of time (see video).  Register online.