I saw your teeth
All participants stand in a circle, each with their arms bent either side of their head with their elbows facing the centre of the circle. Each palyer must curl their lips around their teeth so that no-one can see their teeth a topic is decided, eg animals, and each person in turn must say the name of an animal - difficult with their lips around their teeth! If somebody laughs and reveals their teeth, or reveals them when saying something everybody else must flap their arms around whilst shouting "I saw your teeth!" without showing their own teeth!