Doubleheader is the term used to describe two baseball games played between the same two teams on the same day. Baseball is popular in the Americas and East Asia. ...

Today, a doubleheader is generally the result of a prior game matching the same teams postponed due to inclement weather. Most often the game is rescheduled for a day on which the two teams play each other again. In some cases, this may be weeks or months after the original date. Formerly, however, originally-scheduled doubleheaders were a regular feature of the schedule; this changed when the Major League Baseball Players' Association won a package of concessions from the owners, which, in addition to virtually abolishing fixed doubleheaders entirely, also called for no team ever to be scheduled to play on more than 19 consecutive days.

There are two types of doubleheader games, day-night and twi-night doubleheaders. A day-night doubleheader is one in which the first game is played in the early afternoon and the other is played at night; in this scenario, spectators have to pay twice to gain admittance to both games. In a twi-night doubleheader, the first game is played in the twilight, or late afternoon; then fans get to see both games for the price of a single ticket. Twilight in Denmark, just after sunset Twilight is the time before sunrise and after sunset when sunlight scattered in the upper atmosphere illuminates the lower atmosphere and the surface of the earth. ...

The term doubleheader has also been expanded by network television to refer to two games in any sport aired back-to-back on the same network, even though they do not involve the same two teams (three such games may be referred to as a tripleheader, this scenario being encountered most frequently in basketball). In football, the two networks covering Sunday afternoon games — FOX and CBS — take turns airing doubleheaders during the regular season (with the other network only being permitted to broadcast one game in a specific market), with restrictions applying to any market in which the local team is playing at home that week. Basketball is very popular in U.S. colleges. ... United States simply as football, is a competitive team sport that is both fast-paced and strategic. ... The Fox Broadcasting Company, usually referred to as just Fox (the company itself prefers the capitalized version FOX), is a television network in the United States. ... CBS (Columbia Broadcasting System) is a major television network and radio broadcaster in the United States. ...

The original usage of "doubleheader" is attributed to the 1900's railway industry to refer to two locomotives pulling a particularly long and heavy train (cit. Railroad Commission of Texas, http://www.lib.utexas.edu/taro/tslac/10226/tsl-10226.html)