Just like the title says. Hundreds of non-profit theatre companies from over a hundred cities are inviting people to claim free tickets to their productions on or about October 16th this year. Check out http://www.freenightoftheater.net/index.cfm and see if a city near you is offering free tickets, and what shows are available.
These are non-profit theatre groups, so don’t expect to be able to get Broadway type shows. The main goal is to raise awareness of what is being done by amateur and semi-professional theatre groups in your local area. Tickets generally become available on Oct 1st and there are a limited number available for First Come First Served. Most shows are on Oct 16th(a Thursday) but a lot of companies have multiple shows/nights available.
Comedy, tragedy, Shakespeare, musicals, they’re all out there. There’s even a special site just for New York(which is new this year). 5000 free tickets to over 100 NYC theaters.