You already have nice visuals for black holes, I think it would also be cool to see features for AGNs.
So my suggestion is either just a rendering (without simulation) of components like the accretion disc, torus and jets. If it's not actually simulated, maybe let it just depend on the mass of the black hole, so that the supermassive ones (in the center of galaxies) show the components, but not the regular ones with masses like stars.
Or even cooler (but possibly costly in processing power) simulate the components based on the black hole's mass and how much mass ends up with the right velocities in the right distances around it to build up the torus and accretion disc and eventually spiral in.
Additionally there could be a tutorial or activities explaining AGNs and maybe concepts like the unified model, dynamic friction in the accretion disc, emission/energy production and the Eddington luminosity (limit on emission where outwards photon pressure becomes as strong as inwards gravity) and mass measurements using the virial theorem.
AGN illustration:
Active galactic nuclei info:
http://en.wikipedia.org/wiki/Active_galactic_nucleus