[ODE] Simulating Magnetism...

[Geoff Carlton]

The point about making attached objects into offset geoms (without a 
body) is a must.  There's no way you want to simulate hundreds of 
objects attached with fixed joints and against each other stuck to the 
ball.  Also like that game does, you'll want to eventually strip out the 
inner geoms from the simulation/render as well.  Apart from that, it 
seems doable.

Geoff