Richard Powell's Atlas of the Universe uses a sequence of increasingly enormous maps to place the Solar System, Milky Way, nearby galaxies, superclusters, and the visible universe into one understandable scale.
The Millennium Simulation Project paired one of the largest cosmology computations of its era with a brutally practical web page full of DivX movies, giant images, PostScript posters, and downloadable galaxy catalogues.
NASA still hosts pages from POLAR, a late-1990s and early-2000s experiment that searched for large-scale polarization in the cosmic microwave background with a ground-based microwave radiometer.
Vojtech Ullmann's AstroNuclPhysics site combines nuclear physics, radiation medicine, relativity, cosmology, electronics, philosophy, music and personal material in a sprawling hand-built reference system.