I usually start this game myself to avoid giving long instructions. I say: “Guess the object I’m thinking about.” The students can only offer objects, asking for example, “Is it a car?” and I reply, “No, it’s smaller than a car.” or depending on the level, “No, it’s less mobile than a car.” “Is it a flower?” “It’s less natural than a flower.” and so on. The idea is to use comparatives to get to the object. You could get students to work in teams and take notes. When they’ve guessed the object, someone else takes the ‘hot-seat’.