This ear I am teaching in a new school and in a new district.  One of the district focuses in STEM.  I wanted to challenge myself and my students to daily work on developing and honing problem solving strategies and teamwork, particularly with hands on activities.  I spend the year seeking different games and activities that were very simple to create and maintain and that the students were able to do independently after a initial practice.  Tic Tac Toe came up as a familiar enough game that it was easy for most student to catch on to, but with enough strategy involved to keep them engaged.