My next novel, Eastern Standard Tribe, (due out in just a few weeks!) revolves around the way that your sleep schedule determines a lot about your social circle and hence your beliefs, alliegances, and so forth. A friend of mine in DC who used to work for the CIA just read the book and wrote to point out that the military has been running timezone-tribes for years, so that all the people commanding and supporting some distant operational unit are rising and sleeping on a schedule synched with daylight hours in some far corner.
But I bet they don't get cool watches like this one -- someone should manufacture and sell 'em. My sleep-schedule is so scr0d that I would happily wear this thing and abide by what it told me about my circadian.