As far as I know, all the schools in our area operate a two week timetable (apart from DD's initial comprehensive, where it did but in year 7 the two weeks were identical, if you see what mean). They all manage to timetable Games and PE and compete against each other and in wider competition (DS2 isn't at all sporty, but his school seems to win lot of things, even without his input

). The matches are usually after school and at the weekend, though, so not affected by when actual Games / PE lessons are timetabled by the individual schools.