Thanks to Faithful Provisions for the following info:
If you live close to a minor league baseball team, you can take advantage of BOGO Free tickets on Tuesday nights. From April 13th through September 7th, bring a Kraft Singles package wrapper (just the wrapper!) to the ball park box office where you can purchase a Tuesday night game ticket and get one free.
There are some minor league teams that aren't participating, so be sure to check the "fine print" for a list.
You can find a list of the teams by state online (scroll down past the map).