Worksheet for pair/group activity (written/spoken): invent a sport (make up the rules, number of players, etc.). Practice sports vocabulary and verbs (action verbs, etc.). For more advanced groups: you can then make up a jury with the other groups and have them vote each of the invented sports to see which one they think would be more successful, or which one could/should be designated an olympic sports (practice the use of could/should + argumentation & opinionating).
