This is a really good ice breaker exercise for groups of 10 upwards.  Take a selection of interesting photographs or postcards and cut them in two.  Place each half in an envelope.  Then give an envelope to each group member (making sure that their picture ’pair’ is given to someone they don’t know).  Their task is to find the person who has the other half of their picture and introduce themselves (and any other task you fancy setting them).