Action
Dominated by physical action and external conflict. High energy, big-budget physical stunts and chases, possibly with rescues, battles, fights, escapes, destructive crises, non-stop motion, spectacular rhythm and pacing, and adventurous, often two-dimensional heroes battling bad guys - all designed for pure audience escapism.
Examples: Die Hard series, Cliffhanger (1993), The Incredibles (2004)
Adventure
Exciting stories, with new experiences or exotic locales. They can include traditional swashbucklers, serialized films, and historical spectacles, treasure hunts, disaster films, or searches for the unknown.
Examples: Indiana Jones series, Lara Croft: Tomb Raider series, Back To The Future series (1985)
Comedy
Light-hearted plots designed to amuse and provoke laughter by exaggerating the situation, the language, action, relationships and characters.
Examples: Meet The Parents (2000), Mrs. Doubtfire (1993), As Good As It Gets (1997)
Crime
Developed around the sinister actions of criminals or mobsters, particularly bankrobbers, underworld figures, or ruthless hoodlums who operate outside the law, stealing and murdering their way through life. A cautionary tale, rooted in a main character who commits crimes. Often blended with Film Noir.
Examples: The Godfather series, Heat (1995), Goodfellas (1990)
Drama
Serious, plot-driven presentations, portraying realistic characters, settings, life situations, and stories involving intense character development and interaction.
Examples: Dolores Claiborne (1995), Girl, Interrupted (1999), Schindler's List (1993), Taxi Driver (1976)
Epic
Film with large dramatic scope or that requires an immense production. Take an historical or imagined event, mythic, or heroic figure, and add an extravagant setting and lavish costumes, and a sweeping musical score.
Examples: Lawrence of Arabia (1962), Titanic (1997), Braveheart (1995)
Horror
Designed to frighten and to invoke our hidden worst fears, often in a terrifying, shocking finale, while captivating and entertaining us at the same time in a cathartic experience.
Examples: Psycho (1960), The Shining (1980), The Ring (2002), 
Cube (1998)
Melodrama
The emphasis is on human emotion, illness and physical hardship. Often critical of social and political situations. Clear distinctions exist between good and evil, hero and villain, and right and wrong. Often, the term 'melodrama' is used pejoratively to connote unrealistic, pathos-filled tales of romance or domestic situations with stereotypical characters that would directly appeal to feminine audiences.
Examples: Forrest Gump (1994), Terms of Endearment (1983), Legends of the Fall (1994)
Musical
Emphasize full-scale scores or song and dance routines in a significant way, or that are centered on combinations of music, dance, song or choreography.
Examples: Chicago (2002), Moulin Rouge (2001), Grease (1978)
Mystery
Explores the unsolved crime, particularly murder, disappearance, or detective, investigative intrigue. Emphasis is usually placed on the central character - the hard-boiled detective-hero, as he/she meets various adventures and challenges in the cold and methodical pursuit of the criminal or the solution to the crime.
Examples: The Usual Suspects (1995), Dial M For Murder (1954), Mystic River (2003)
Romance
Love stories that center on passion, emotion, and romance between characters, and the journey that their love takes. Characters who want to win or keep the love of another.
Examples: Casablanca (1942), Sleepless In Seattle (1993), Pretty Woman (1990)
Science Fiction (Sci-Fi)
Often quasi-scientific, visionary and imaginative - complete with heroes, aliens, distant planets, impossible quests, fantastic places, great dark and shadowy villains, futuristic technology, unknown and unknowable forces, and extraordinary monsters, either created by mad scientists or by nuclear havoc. Science fiction often expresses the potential of technology to destroy humankind.
Examples: Star Trek series, The Terminator series, 2001: A Space Odyssey (1968)
War
Acknowledge the horror and heartbreak of war, letting the actual combat fighting (against nations or humankind) on land, sea, or in the air provide the primary plot or background for the action. Include POW tales, stories of military operations, and training.
Examples: Saving Private Ryan (1998), Platoon (1986), Black Hawk Down (2001)
Western
One of the oldest, most enduring genres with very recognizable plots, elements, and characters such as: horses, dusty towns, cowboys, Indians, train robberies, gun fights, rugged terrain, sheriffs and outlaws. Portray the early days of frontier America and the legends that arose in the Western part of the country during the late 1800's.
Examples: The Magnificent Seven (1960), The Unforgiven (1992), Dances With Wolves (1990)