AKA "That's Entertainment!"
1974 film written and directed by Jack Haley, Jr. featuring a compilation of clips from MGM musicals, introduced by Hollywood stars who appeared in many of them (Fred Astaire, Debbie Reynolds, Gene Kelly, Donald O'Connor, Mickey Rooney, James Stewart, Peter Lawford, Bing Crosby, Elizbeth Taylor, and Frank Sinatra). Liza Minelli, who appeared only in one MGM musical at the age of two, introduced clips featuring her mother, Judy Garland.
Film critic Roger Ebert called this tribute documentary a "eulogy": the golden age of Hollywood musicals (the 1920s to the 1950s) was over and at the time of the film's release MGM itself was being dismantled (assets like business units and famous props alike (e.g. a pair of ruby slippers from The Wizard of Oz) were being sold off). Some of the film showed the once-famous-now-neglected backlot in disrepair; at the time of shooting it had already been sold to real estate developers.
The film's nostalgia appealed to a segment of the moviegoing audience who grew up on these musicals, and who may have found the film a welcome change of pace from the relentless trend of American dramas featuring anti-heros and reflecting the social and political upheavals of the late 1960s and early 1970s. The film's box office success led to immediate work on a sequel, That's Entertainment II, released in 1976. Haley would later go on to produce That's Dancing in 1985 (which cast a broader net than solely MGM film history), and MGM created another sequel, That's Entertainment III in 1994.
The film's theme song, "That's Entertainment," was written by Arthur Schwartz and Howard Dietz for MGM's 1953 film adapatation of the Broadway musical, The Band Wagon, where it was sung by Oscar Levant, Nanette Fabray, Fred Astaire and Jack Buchanan.
Sources:
IMDB, "That's Entertainment," Internet Movie Database, http://www.imdb.com/title/tt0072272/ (November 6, 2012)
Roger Ebert, review, Chicago Sun Times, January 21, 1974. http://rogerebert.suntimes.com/apps/pbcs.dll/article?AID=/19740101/REVIEWS/401010320/1023 (november 6, 2012)
Rick Lyman, "Jack Haley Jr., 67, Dies; Known for 'That's Entertainment'" New York Times. April 23, 2001. http://www.nytimes.com/2001/04/23/arts/jack-haley-jr-67-dies-known-for-that-s-entertainment.html (November 6, 2012)
Nora Sayre, review, May 24, 1974, New York Times. http://movies.nytimes.com/movie/review?res=9C0DE2DE153AEF34BC4C51DFB366838F669EDE (November 6, 2012)
Thomas Schatz "MGM (Metro-Goldwyn-Mayer), Film Reference,
http://www.filmreference.com/encyclopedia/Independent-Film-Road-Movies/MGM-Metro-Goldwyn-Mayer-STRUGGLE-DECLINE-AND-DISMEMBERMENT.html, (November 6, 2012)