OK let's see, those light beams, definitely DMX lighting companies provide IES profiles, but the atmospherics, man the volumetric bounds will have to be thick and highly scattering... and even using low-poly Poser exported meshes for the tens of thousands of phamily, assuming I could script the backface culling to minimize the millions upon millions of verts... well, at least the texturing is simple, you can't see the color of anyone's clothes, it's just the color of the effects lighting, plus all the LED toys and cell phone screens and glow sticks... and since everyone is standing you don't have to model the arena seats, that's a huge savings...
Wait, what song is this?
