For anyone who finds the Connes-Marcolli paper we recently linked to heavy going, Lieven Le Bruyn recommends some lighter reading: an interview with Alain Connes himself from the conference in Tehran where the paper was presented. In the interview Connes talks about physics and noncommutative geometry. He also has some sharp criticisms with how mathematics research works in the United States in comparison to France (where he lives and works).
Peter Woit also discussed this interview a couple of weeks back.
[...] Alain Connes, who we’ve talked about before, has added something very exciting to his website: the text of his famous book Noncommutative Geometry as a pdf. There is nothing quite like Connes’ book. It’s part popularization, part research monograph, and part manifesto. I highly recommend taking a look. [...]