One of my guilty pleasures is reading pop science books, especially on esoteric particle physics and cosmology. One of the best writers in the genre is Columbia University physics professor, Brian Greene, whose first two books were The Elegant Universe and The Fabric of the Cosmos. Greene is a proponent of string theory, which is a beautiful if unproven (unproveable?) hypothesis about the deep structure of atomic reality. (Lee Smolin wrote a good book a few years ago about the problems with string theory, called The Trouble with Physics.)
Anyway, Greene has a new book out that I'm reading now called The Hidden Reality, which describes in fascinating and sometimes funny chapters how modern physics may imply the existence of parallel universes where another me (or infinite me's) is sitting in the same music store waiting for the same (or slightly different?) son to finish guitar lessons and writing on his parallel blog about someone named Brian Greene who also writes books about parallel universes except millions or even billions of light years from here. It's a fun book so far, if you're secretly a nerd, like I am.