Back in 1985, the world was blessed with Back to the Future, a rollicking yarn about a teenager who befriends a weird old man who may or may not be helping terrorists build a nuke, then travels back to 1955, where he must fend off the sexual advances of his horny teenage mother to make it back to 1985. It's fun for the whole family!

Robert Zemeckis' trilogy—which jumped to the far-flung future of 2015 in Part II and then the Old West of 1885 in Part III—is one of the most beloved series of its generation. Portland's Back to the Future Day (Wednesday, Oct. 21) festivities include a trilogy party at the Clinton and a huge McFly Arrives bash at Dante's, with costumes, live music and live karaoke.

Expect poodle skirts, vests that look like lifejackets and lab coats. But sometimes, the deeper cut is the best. So AP Film Studies consulted its wardrobe department for a few less-obvious costume choices.

Marvin Berry

Marvin, the lead guitarist of the Starlighters—the 1955 high-school dance band whose sweet sounds amped Lorraine's desire to unknowingly get it on with her own son—badly injures his hand when he tries to free Marty from a trunk while high.

Props: Old-school guitar, black pants and tie, super-shiny blue blazer with black lapels, bandage on the right hand.

Jaws 19

People go apeshit over the whole "what did Back to the Future Part II predict correctly about 2015" thing, from self-lacing shoes to drones to flat-screens. But they never mention how the gag about Jaws 19 predicted Katy Perry's infamous dancing sharks from her acid-trip Super Bowl performance. Robert Zemeckis should sue over that shit. It's a dead ringer.

Props: Just a cheap Left Shark costume will do.

2015 World Championship Cubs player

"Hey, the season's still young, it could still happen," says every Cubs fan at the beginning of every season for the past century. Back to the Future Part II predicted 2015 as the year the Cubs would win. That will be wrong. But this is a fantasy film.

Props: Cubs jersey, novelty trophy, a straight face.

ZZ Top

The duo did Part III's theme song and showed up in the film looking very much like ZZ Top, but with cowboy hats. This is the easiest costume, especially if you're already a beardo.

Props: Cowboy hat and coat, guitar or marching drum, fake beard (or Duck Dynasty costume).

Manure

Manure is as important to the BTTF universe as flux capacitors and Oedipal complexes. Cover yourself in clumps of brown fabric, then stage-dive on anybody dressed as one of the Tannen clan. Best-case scenario? He screams, "Manure! I hate manure!" Worst-case scenario, you get slugged in the face. Either way, the Tannen is in character.

Props: Lots of fake poop and a mouth guard.

GO: The Back to the Future marathon party is at the Clinton Street Theater on Wednesday, Oct. 21. 5 pm. All ages. The McFly Arrives party is at Dante's on Wednesday, Oct. 21. 9 pm. 21+.

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Also playing:

Weird Wednesday brings the A-game with an ultra-rare 3D screening of the Vincent Price classic The Mad Magician. 9 pm Wednesday, Oct. 21.

Pianist Beth Karp provides a live, original piano score to the classic 1920 horror fantasy The Golem. Kiggins Theatre, 7 pm Thursday, Oct. 22

Often overlooked among '80s kids movies, The Monster Squad stands well alongside The Goonies with its foul-mouthed kids going up against classic Universal monsters and adopting Frankenstein's as their own Sloth. McMenamins' Kennedy School. Friday-Thursday, Oct. 23-29.

Jacques Boyreau's GrindThis! Grindhouse series continues with low-rent classics like Brain Damage, Demons (plus Demons 2!), Prom Night and Frankenhooker highlighting the roster. Through Oct. 19. See laurelhursttheater.com for full listings.

With all its bulging muscles, explosions and not-at-all-homoerotic camaraderie, it's easy to forget that Predator is actually a solid little slice of survival horror. Just, you know, with the aforementioned things seasoning the pot. 5th Avenue Cinema. 7 & 9:30 pm Friday-Saturday, 3 pm Sunday, Oct. 23-25.

Yes, The Exorcist is still as pants-shittingly scary as it was in 1973, and William Friedkin's director's cut manages to up the ante with the simple addition of a spider walk. Good luck getting that out of your head. Academy Theater. Friday-Saturday, Oct. 23-31.

In 1993, Disney released Hocus Pocus, a movie seemingly designed to bump Ernest Scared Stupid off its "terrible kid-friendly Halloween movie to put on while the parents drink" throne. Apparently, it worked, because here we are, two decades later, with Bette Midler on screen and no sign of Jim Varney. Sigh. Hollywood Theatre. Saturday-Sunday, Oct. 24-25.

Cinelucnafest celebrates Halloween, luchador style, with face painting, masks, and a screen of Santo and Blue Demon Meet Dracula and the Wolfman, which is a lot like the Abbott & Costello version, but with more turtlenecks and luxury sports cars. Hollywood Theatre. 4 pm Saturday, Oct. 24.

Hecklevision takes on Stephen King's coke-fueled Maximum Overdrive, in which a dude getting killed by a soda machine and a child getting smooshed by a steamroller—in the same fucking scene. Cocaine! Hollywood Theatre. 7 pm Saturday, Oct. 24.

The American Genre Film Archive presents Smut without Smut, a one-two punch of raunch featuring 1976's The Haunted Pussy and 1971's The Mad love Life of a Hot Vampire. These two should really hook up. Hollywood Theatre. 9:30 pm Saturday, Oct. 24.

Filmmaker Ron Mann stops by the Clinton for a retrospective of his work. Saturday includes a screening of his documentary Altman (5pm)an in-depth look at the life and legacy of legendary auteur Robert Altman—paired the director's mosaic masterpiece Nashville (8 pm). Sunday features 1988's sprawling Comic Book Confidential (4 pm) and 2008's Know Your Mushrooms (7 pm), a look at the wild world of fungi. Clinton Street Theater. Saturday-Sunday, Oct. 24-25.

Back to the Future might be hogging this week's anniversary glory, but it's Goodfellas' 25th anniversary this year as well, not that it's left 60% of our DVD players for more than a week during that time. Cartopia. Dark, Sunday, Oct. 25.

POW Monthly presents Mary Lambert's adaptation of Pet Semetary, a film that strikes a weird balance between camp and genuine chills, but nonetheless features Herman Munster's finest performance. Clinton Street Theater. 7 pm Monday, Oct. 26.

The Horror in the Woods Double Feature pairs 1980's Mother's Day with 1982's Madman Marz, two films sharing the distinction of being, um, horror movies set in the woods. Hollywood Theatre. 7:30 pm Tuesday, Oct. 27.