going to Maui with a good book. For shorter amts of quiet time, I like to play a mind-numbing game of Chuzzle with the sound turned off. Yes, it's a game for kids, but it's like meditation and the little Chuzzles crack me up.
Writing articles on hubpages and suite101 is also a good way to get away from everything. I really love it.
A walk through the neighborhood at 3AM. Not a peep, and everyone safely holed up in their homes. You don't really realize how vulnerable they are until you look at them when no one else is around. It gives you a different perspective.