Who'd be in your league? Who'd be the villain(s)? How would it all come together? Etc. I love reading everyones ideas and seeing different takes, I'll post my idea soon. So post away
My League movie would be pretty straightforward.
Basic Plot: As metahuman activity increases worldwide, mental and physical powerhouse, Despero comes to lay claim to Earth for his dark master.
Heroes: Batman, Green Lantern, Superman, Wonderwoman, Flash.
Cameos: Martian Manhunter, Aquaman, Hawkman, Hawkwoman, Zatanna
Villains: Despero, Ultramarines, foreshadow Darkseid
Supporting: General Eiling, Amanda Waller, Lois Lane, Alfred, Linda Park, Salaak, Lex Luthor
Basic Scene Breakdown:
The movie opens up at a Metahuman conference. Flash and GL are there as heroes (they have public IDs) while Bruce Wayne, Clark Kent and Diana of Themyscira are all there for civillian reasons, along with Lex Luthor and General Eiling. A demonstration of the government's answer (Ultramarine chariacatures) to metahumanity goes awry, prompting the intervention of the two guests of honor as well as Superman, Wonder Woman and a mysterious well placed Batarang from the crowd. And there's some rude comments from Eiling about aliens.
These events lead to the activation of a sattelite that attracts a passing "asteroid's" attention. It veers off and we get shadows and maybe a glimpse of a midnight purple hand grabbing onto the Space Station, with Astronauts and Cosmonauts going all purple eyed.
We cut to the Space Shuttle coming down, crashing, Superman and GL are on the scene, they catch it, and land it safely, and after a sequence of purple eyed innocent bystanders questioning them, Despero bursts from the shuttle, outmuscling supe and slowing GL with innocents before denouncing earth's corrupt heroes and stalking off to go build his army, heading East.
Superman and GL decide to split duties. GL goes to Oa to research and Superman goes around recruiting heroes. Hawkman and Hawkgirl turn him down, prefering their civillain lives this reincarnation. Aquaman can't be bothered. Wonder Woman says she'll think about it. Clark Kent goes to interview Bruce Wayne, but when they get down to it, Bruce thinks its a horrible idea. (Supes notices Batman begin to lead-line the cave). Zatanna feels it's over her head. Flash is naturally in and they go to Europe to recon where Despero is taking on tanks and then adding them to his ranks. Turns out Batman is there and gets Desperoed for a moment before he moves out of range and retreats back to his lab. Meanwhile, Superman gets mindjacked and Flash can barely survive the attack, until he out races Superman out of Despero's range.
Meanwhile, Green Lantern meets with General Eiling, along with undercover Diana Prince, giving a tour of Area 51, which may have to do with the Despero Crisis. Turns out the government has a puddle of unstable martian lifeform there that hid out on Earth's moon. J'onn tells the heroes what Despero is all about, and how dire the situation is. GL, WW, Superman and Flash agree to meet up in Happy Harbor. (Maybe a moment to tribute/cameo the Justice Society). Together they discuss their next movie, have arguements and suspect Batman, who emerges from the shadows and (Before a fight even starts) cleverly defeats all but Wondy, who, truth insured, agrees that he is Despero-free and on their side.
The final conflict looms, Despero approaches the USA's West Coast, all of Europe and Asia's Naval and Airforces leading the way, with Nukes armed as well. The four heroes battle, only to find Eiling's Ultramarines brainjacked by Despero, making things that much harder. Superman and Wonder Woman double team Despero as Batman works his way in to help the group resist Despero's sound/vibration-based mind-control. Batman has some soundjammers, he shows GL how to do it and Flash outvibrates the effect while Wonder Woman's lasso saves her and Superman fights the effect on pure willpower.
Big Giant, mountain-crushing, state-spanning, jaw-dropping battle. Make DBZ look like kid's doodles.
(ie, Despero uppercuts Wonder Woman in LA and she lands in San Francisco)
(ie, Flash punches Pulse8 in Phoenix, snatches some civillians from a bombing in Seattle, pummels some thugs in Vegas and then puts in another hit for Pulse8 in Phoenix again, all in the same ten seconds)
(ie, Superman gets nuked, and then staggers out of it, clothes in shreds, trying to stand, then readying himself to fight a menacing Despero)
(ie, GL emerges from charging his ring with a green army backing him up)
So the heroes finally defeat the Ultramarines and Despero, ending his control of the world army, Despero gives some speech about how the world fears their awesome power, and how weak this world is and how easily it will be controlled by his dark master. Eiling comes to 'rightfully' collect him, but Wonder Woman barters Despero for the martian's freedom. With J'onn's intervention the heroes agree on meeting date to talk about Metahuman affairs... and a name. The Justice League of America.
www.geocities.com/jlamovie
At least... that's how I would do it.