Here are the dry facts:
Daylight Saving Time originally began in the USA during WWI in order to save energy for war production, utilizing the later hours of daylight between April and October. In WWII the USA government instituted the practice again. Congress passed the Uniform Time Act in 1966 which standardized Daylight Savings Time.
Some USA states and territories don't have to worry about it. Daylight Savings Time is not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands, the Commonwealth of Northern Mariana Islands, and Arizona.
Most of Canada uses Daylight Saving Time. Some exceptions include the majority of Saskatchewan and parts of northeastern British Columbia. In the fall of 2005, Manitoba and Ontario announced that like the United States, they would extend daylight time starting in 2007. Other provinces have indicated that they may also follow suit.