national geographic
excerpt:For most Americans, daylight saving time ends in 2010 at 2 a.m. on Sunday, November 7, when most states fall back to standard time.
Time will spring forward again on March 13, 2011, when daylight saving time resumes.
The federal government doesn't require U.S. states or territories to observe daylight saving time, which is why residents of Arizona, Hawaii, Puerto Rico, the Virgin Islands, American Samoa, Guam, and the Northern Marianas Islands won't need to turn back their clocks this weekend.
Where it is observed, daylight savings has been known to cause some problems....read more
