Simon Schama's Power of Art is available in full. Part 1 Caravaggio. Part 2 Bernini. Part 3 Rembrandt. Part 4 David. Part 5 Turner. Part 6 Van Gogh. Part 7 Picasso. Part 8 Rothko. [more inside]
If you like 'fantasy' art (as opposed to comics :) and you're in DC I'd highly recommend checking out the JMW Turner exhibit at the NGA! [more inside]
Turner Worldwide. The Tate's new online Turner project brings together works from over 100 collections, including about 500 previously 'lost' pieces.