How is this done ?! advanced physics

hi there mates!
well…dont know where else to ask this so here it goes.

how in the hell is this advanced colision done?!?!
i mean, beside the gravity, the objects also rotate while hitting each others…

check it out here:
http://www.theturn.tv/

i’ve seen this in another fwa award too…
can anyone point me out in the right direction? i need help in the physics, not in the colision detection…

thanks in advance!
cheers