Galaxy Quest: Actors from an old TV show are contacted by some obsessive fans who need help dealing with someone named after a famous film critic. The fans turn out to be tentacle aliens, and they have sex with one of the actors.
Or: Tim Allen is in a movie whose plot revolves around the fact that he's famous. Monk helps.
Gamera 3: Awakening of Irys: Girl seeks revenge against a giant turtle. Giant tentacled monster offers his help only to manipulate the girl's emotions for his own gain. Oh, and the giant bat-monsters come back.
Gangs of New York: An angry orphan comes to a rapidly growing city during wartime. He nearly gets mugged by a woman with a shifting accent before going to work for a mustachioed, plaid-wearing hypocrite. He starts to forget why he came to the city in the first place, but then is set straight by a self-proclaimed Shakespearean scholar while a celebrity impersonator hovers above their heads and gets fruit hurled at him. Later on, an elephant stampedes through blood-soaked streets.
Gattaca: A man who may or may not be terminally ill steals his roommate's identity in order to fulfill his childhood dream, which will almost certainly put his coworkers' lives in danger. Later, he seduces a woman with no intention of revealing his true identity to her, then proves that he isn't mature enough to cope with his sibling-rivalry issues. In the end, the protagonist fulfills his dream while his roommate commits suicide in an incinerator.
Get Shorty: Mob-connected loan shark discovers he's a natural Hollywood player.
Be Cool: Disgruntled natural Hollywood player fights against, participates in and makes beautiful music with organized crime.
Godzilla Final Wars: A mustachioed Bad Ass and his crew release giant dinosaur he once imprisoned to stop the invasion of leather wearing aliens by beating the shit out of all the monsters they control. Also, one of the crew members is the Japanese equivalent to Neo.
Godzilla (1998, American): Sea critter gets stuck with a misnomer and tries to nest despite humans disturbing the area.
Godzilla (2014, American): Sea critter awakens to break the honeymoon of a particularly destructive couple.
Gone with the Wind: A spoiled bitch and a lecherous scoundrel fight for chattel slavery to be made a substitute against both wage slavery and the use of taxes to transfer money from one place to another. They're our heroes.
Or: The protagonist feeds his ill, bed-ridden mother outrageous lies to fool her into thinking she lives in an oppressive socialist state.
The Good Dinosaur: Set in an alternate history, an orphan becomes friends with a small boy.
Good Will Hunting: A therapist, a mathematician, and working class roughs vie for the soul of a really smart janitor.
Goodfellas: A kid gets a job parking cars for the people across the street and talks about the things his employers have him do.
A Goofy Movie: Reject from the Disney Animated Canon, featuring wacko suburbanite and his son on a physically dangerous Road Trip. One of them ends up on stage at a concert by a performer who appears to be a cross between Prince and 1980s-era Michael Jackson. A fly-fishing move becomes a dance move and helps the father with his audience.
The Goonies: A hobbit and his friends try to find some treasure that was buried in a cave. They end up not getting to keep much of it.
Gorgo: Irish mother travels to London to rescue her kidnapped son. Visits various monuments and destroys them.
Gorillas in the Mist: The inspiring true story of a white woman who goes to Africa and spends most of her time hanging out with apes while pissing off a lot of black people. Ultimately she is mysteriously murdered after trying to interfere with said black people's way of making money.
Gosford Park: Love and intrigue at a 1930s British house party. Michael Gambon is murdered twice.
Planet Terror: Woman quits dancing the same day she becomes crippled. Gets used to her new prosthetic limb, though. Also, zombies happen.
Death Proof: Women who are tired of putting up with celebrities go and rent a car, kill an ex-stunt guy who drives his cool car around.
Grosse Pointe Blank: Man facing existential crisis attends his ten-year reunion to get back together with his high school sweetheart, even if he is unable to get rid of his work while there.
Groundhog Day: A journalist falls into a time loop, and kills himself and a woodchuck several times. Eventually he becomes enlightened.
Or: Big town weatherman experiences small-town life.
Guardians of the Galaxy: Exhiled orphan steals a metal ball, leading him to misunderstandings with an agressive girl, plus a duo of a grumpy shorty and a dimwitted giant, that get them all arrested. They are forced to team up, along with a Literal-Minded muscular angry guy, to break out of prison and try to get rid of said ball.