I sent this article to a math whiz soccer player from my Precalculus class. She was as excited as you would expect to be sent an article about math over the summer. It involves using vectors, dot products, and contour mapping to determine where to place a wall of players during a free kick. Fascinating stuff, and easy enough to understand for Precal or advanced Geometry students.
http://www.wired.com/2014/06/angular-size-of-a-soccer-goal/