Some research takes so much computer power, that it is almost impossible for any university to do it. But get a whole stack of people to link their home computers and wonders happen. Global computing communities search for prime numbers, alien intelligence and the wonders of fractal art. In this unit, students meet these communities and some of the leading personalities in them. Fascinating people and fascinating obsessions. And all are open to anyone to join in. Free. Is this a change in the whole way the world works?