"Mr. Mom" Comedies
If the history of PG-rated comedies have taught us anything, it's that grown men posses virtually no nurturing instincts whatsoever, and are incompetent at raising children to the point of felonious neglect. "Mr. Mom" comedies, named after the 1983 Michael Keaton movie of the same name, relishes in the stereotype of the ignorant stay-at-home male. No sooner is it that Mom steps out the door that Dad, a male au pair, or any male entrusted with the well-being of kids, is rendered useless in 90 minutes of toddlers swinging on lampshades and infants pissing on his chest during ill-fated diaper changes.
Examples Include
"Mr. Nanny," "Daddy Day Care," "The Pacifier," "The Game Plan," "Cheaper by the Dozen," "Are We There Yet?" "Cheaper by the Dozen 2," "Mr. Mom"
Common Scenes
-Comically contrasting "tough-guy" casting (e.g. Hulk Hogan, Vin Diesel)
-Dog, toad, or other household pet running rampant through house
-Skateboards hazardously placed atop staircases

'90s Cyber-Thrillers

Hard as it may be to imagine in a present where every suburban household in the country sports a Compaq 2600 in the family room and the Internet's most exciting uses include downloading "300" and watching Asian pornography, computers were once viewed with awe and terror. In that long-ago decade known as the '90s, the "World Wide Web" was a (literally) virtual battlefield in which Keanu Reeves combats cyber-terrorists, Sandra Bullock exposes deadly government secrets, and Russel Crowe has an American accent.
Examples Include
"Lawnmower Man," "Johnny Mnemonic," "The Net," "Virtuosity," "Strange Days," Hackers
Common Scenes

-Protagonist donning comically oversized virtual reality helmet
-Neon green and pink color scheme throughout film and film advertisements
-Digital "Maguffin" in form of microchip, miniature CD-ROM, or floppy disk containing incriminating data

"Robot Who Yearns To Be Human" Films
When the hell did Earth's robots become such crybabies? There was a time when automatons were ass-kicking chromium skeletons laser-blasting their way through the wasteland that was Earth and reigning over mankind as our cruel overlords. Now, with the exception of the occasional "Terminator" sequel or Will Smith vehicle, robots just wander around quoting great books and wondering what love is like some walking, talking Foreigner song. In John Connor's day, the only way of bringing down a cybernetic assassin was pushing it into a vat of molten metal, now the biggest threat Johnny 5 poses is an annoying string of John Wayne impersonations.
Examples Include
"A.I.," "Bicentennial Man," "Short circuit," "Short Circuit 2," "Robocop," "Robocop 2," "The Day the Earth Stood Still," "Terminator 2"
Common Scenes
-Robot cruelly hunted by ruthless, misunderstanding humans
-Robot mimicking pop-culture phrases and quotes
-Vague allusion to possible humanity inside robot's consciousness

"No Adults! No Rules!" Comedies
Take a group of 13-year-olds, take away their parents, and you've got… "The Lord of the Flies" (or "Children of the Corn"). But throw in a cozy suburban home to destroy or a bundle of cash to spend, and you've got Hollywood's vision of every American pre-teen's dream: Race cars in the backyard! Ice cream for breakfast! A water slide in your bedroom! Most films from this genre are basically (and I'm aware how disturbing this is going to sound) porno for kids: Unlimited toys and no parental guidance. An orgy of video games and candy, obtained by any means necessary-although usually by embezzling their parent's money. Except "Blank Check," of course. He just commits straight up check fraud.
Examples Include
Camp Nowhere, Home Alone, Home Alone 2: Lost in New York," House Arrest, Adventures in Babysitting
Common Scenes

-Cold, work-obsessed parents too busy with professional life to notice lonely children
-Large shipment of expensive toys, vehicles, candies delivered to kid(s)
-Jean jacket-wearing "tough kid" lovingly bullies younger kids

"Detective, Your New Partner's A Dog!"
Scientists perfected the buddy cop formula in 1987 with "Lethal Weapon," but they created nearly as many problems as they solved. How do you innovate a movie that good? How do you find two buddies even less likely to get along than Murtough and Riggs? They had no choice but to start pairing up different species. The genre flourished from the late '80s to early '90s until the discovery of the "stunt man-wise ass postulate" and "Rush Hour." These days, movie cops are more likely to be paired with CGI creations, but researchers have announced that the long delayed cop-and-a-monkey genre should be arriving in theaters before the end of the decade.
Examples Include

"Turner and Hooch," "K9," "Kuffs," and "Top Dog."
Common Scenes

-The cop is in disbelief when he meets his new partner, but the chief does not want to hear about it
-The dog thinks he's people.-The cop comes home to find his apartment or other precious belonging destroyed by the dog
-The dog tries to lick the disgusted cop right before the credits. The cop tries to fight it, but eventually he gives in and hugs the dog

Human Sucked Into Cartoon World

In the 1920's, Walt Disney produced a series of comedies starring a girl named Alice who dreamed of living in a cartoon landscape. The interaction between actors and animated characters was unlike anything seen before and heralded as a film making break-through. Imagine how excited Walt would be to learn that his technique and imagination would inspire such films as "Cool World" and "Space Jam" for decades to come.
Examples Include

"Who Framed Roger Rabbit?" "Monkeybone," "The Pagemaster" (For the opposite, see "Rocky and Bullwinkle," "Enchanted," and "Fat Albert")
Common Scenes
-A protagonist who has stopped listening to his inner child, or otherwise needs a lesson in having fun
-A human character attracted to an animated female with unrealistic proportions (there's something between Michael Jordan and Lola Bunny, you just have to read between the lines)

The Body Swap

It's easy to see why producers are attracted to stories of souls swapping bodies. It's like two fish-out-of-water comedies for the price of one. The old guy's trying to skateboard! The woman is burping and scratching herself! The white guy can rap! If you don't think that's funny, maybe you're the one that needs to swap bodies and learn an important lesson about how good you really have it. Movies where someone magically grows up or gets younger are closely related to body swapping and share many of the same cliches. However, since only one body is affected they are technically their own sub-sub-genre. Examples include "13 Going on 30, 18 Again," and of course "Big."
Examples Include
"Freaky Friday," "Vice Versa," "Like Father Like Son," "Face/Off"
Common Scenes
-Simultaneous screams when the body switch is discovered
-Awkward sexual tension
-Going to comical lengths to keep the switcheroo a secret