The number of twenty can also be called a score (as Abraham Lincoln did in his Gettysburg Address).
In a game of chess both players have 20 first moves from which to choose
Twenty questions is a popular party game
Twenty is the age of majority in Japanese tradition. Someone who is exactly twenty years old is described as hatachi
The Twenty Year Curse refers to the pattern of presidents of the United States who assumed office in 1840, 1860, 1880, 1900, 1920, 1940, and 1960 to die in office. This pattern ended with the 1980 presidency of Reagan, who survived his time in office and, notably, an attempted assassination.
Bands with the number twenty in their name include Matchbox Twenty
A 20-minute-long entertainment program shown before some films playing in United Artists movie theaters is called "The Twenty" (spelled "The 20wenty")
Yan Tan Tethera is a 20-word jingle for counting sheep
The ordinal adjective is vicenary
20/20 is a late-night newsmagazine program on the ABC network, that has been hosted by Barbara Walters, Hugh Downs, Elizabeth Vargas, and others
In the roleplaying game Dungeons and Dragons (as well as other RPGs that use twenty-sided dice), twenty-sided dice play a pivotal role in gameplay, and to "roll a twenty" is significant to the point that it is sometimes used in other, usually related, contexts, similar to the use of "doubles" in reference to Monopoly.
20 is:

Twenty, a village in Lincolnshire
In the United States Constitution, $20 is the threshold value of civil disputes above which the right to trial by jury is preserved
A denomination of U.S. dollar featuring Andrew Jackson's portrait
A denomination of Pound sterling featuring Adam Smith's portrait
The code for international direct dial phone calls to Egypt
The designation of Interstate 20, a freeway that runs from Texas to South Carolina
20 (album), a 1988 album by Harry Connick, Jr.
Twenty (album), a 1997 album by Lynyrd Skynyrd
20 (Terminaator album), a 2007 album by Terminaator

Yes folks, we're still here giving our version of live as it is in LEOville. The tears the joys and all that comes between.

We were here;
related discussion: to eat s.o. out #19