The logical way to divide a spinning planet into time zones would be to draw 24 latitudinal lines on the globe, leaving equal areas for each time zone. But that doesn't work for people who live with real life geography, national borders, and human nature. Countries did not adopt standard time all at once, and politics plays a big part. So we have some extra time zones that set their clocks a half-hour different from their neighbors, and some places that could use more time zones. RealLifeLore explains some of the weirder anomalies in global time. -via Digg
Eventually we decided "set everything to UTC!" Still a pain, but at least you only have to do one conversion to local time instead of constantly looking it up.