Me too, me too!!
One person starts introducing him/herself (eg. my name is Joe, I come from London, I am 12, etc) and when anyone else in the circle hears something they have in common they shout "Me too, me too!" and everyone else shouts "A link, a link!", at which point that person goes and sits next to the first person. Now it is his/her turn to introduce themselves until thew next person finds and link. Eventually, everyone will be sitting next to someone they have something in common with.