War Reenactors

Exactly What It Says on the Tin: A bunch of people simulating famous battles and wars, especially (if American) the American Civil War. A character already known to be a history, military, or weapons geek will probably be in attendance. Sometimes they'll be the descendant of a famous general.

Examples of War Reenactors include:

Film

Night at the Museum had a whole exhibit of Civil War soldier mannequins that would come to life each night and start fighting each other.
The titular Two Thousand Maniacs are having their own little reenactment with our poor heroes.
The protagonist's father in Sweet Home Alabama is a reenactor.

Literature

Appears in Discworld, though of course it was a different civil war.
- Also, a famous "ambush" in which Dwarfs and Trolls supposedly both set a trap for each other and fought so hard that the Disc cracked and flooded and all participants were swallowed up into the crevices. From then on, every year, almost all Dwarfs and almost all Trolls gang up on each other to fight in a sort of reenactment...but more like an actual war. It turns out that the two sides were actually trying to negotiate lasting peace and were simply caught in a flash-flood, eventually settling down to die together during a nice game of Thud.

Live Action TV

NCIS's Tony DiNozzo senior did Civil War reenactments and gave Tony DiNozzo junior the job of carrying around a bucket for the reenactors to use as a toilet. A childhood of being called their "little poo-boy" gave him a slight phobia of reenactors in general.
The Batley Townswomen's Guild's Reenactment Of The Battle Of Pearl Harbour (A group of women covered in mud, going at each other with their handbags in some field) from Monty Python's Flying Circus.
Psych: A murder occurs during a Civil War reenactment. Lassiter (weapons geek) was role-playing as a Union officer that he claims to be a descendant of.
CSI came across the corpse of a Civil War reenactor in one Cold Open.
That Mitchell and Webb Look had a sketch about reenactors of the English Civil War, who attempt other wars which goes poorly for them.
Micael Moore's TV Nation had a civil war re-enactment troupe re-enact other battles, like "Battle of Hiroshima" (model plane flies overhead, everyone stares and point up, then drops dead) and "Battle of Los Angeles" (Rodney King riots).
A reenanactment of the English Civil War coincides with the awakening of ancient Sealed Evil in a Can in the Doctor Who serial "The Awakening". Its baleful influence turns the reenactors more violent than it otherwise would have been (and comapnion Tegan is almost burnt at the stake).

Video Games

The Ghostbusters game had a fight in a museum full of Civil War Ghosts. The reenactment was inevitable.

Webcomics

Parodied in Dresden Codak with the Historical Pre-Enactment Society, who (pre)enact battles that have yet to happen, with lasers and such.

Western Animation

Parodied in Family Guy when the Griffins live in a backward Southern town. The local reenactors put on a short play which goes as follows:

Lee: "Ulysses S. Grant. You invite me to lunch, then show up late and drunk?"
Grant: "I was lookin' for your wife, to give her the old...(does crude gestures)"
Lee: "That does it. This, sir, means war. (pushes Grant down)"
Grant: "I am vanquished."

A few times on The Simpsons:
- To save money for a nanny, Homer resigned from "the Civil War Recreation Society I love so much."
- Homer must've rejoined, because in a later ep he takes part in a reenactment, which was inaccurate (according to Principal Skinner).
- Springfield Elementary tried to sneak peeks at a reenactment during a field trip, because they didn't have the money to pay to get in; the soldiers (both North and South) chased them away.
- When Homer becomes head of the Stonecutters he hits upon an idea to help the community:

Homer: I'll get a bunch of monkeys, dress them up, and make them reenact the Civil War.
Lisa: Dad, that doesn't help people!
Homer: Couldn't hurt...unless the monkeys start hurting people. Which they almost certainly would.

- Also occured during the first act in "The Sweetest Apu" when Principal Skinner sponsors a Civil War reenactment which ends up inaccurate.
South Park: Cartman as General Lee leads the South to victory to win a bet with Stan and Kyle.
Parodied in SpongeBob SquarePants with a large group of fish dressed in pseudo civil war era uniforms, one army in blue and one in red, reenacting the Battle of Bikini Bottom. Towards the end of the episode there's a rather unnecessary and hamhanded Take That towards actual enthusiasts.
On American Dad, Stan and Steve participate in a Vietnam War re-enactment on a golf course. Steve takes it too seriously and starts acting like a Shell-Shocked Veteran.
On Futurama, the crew takes part in a Sith-il War reenactment. They dress in blue Union uniforms with fake laser rifles while their opponents use lightsabers.
One episode of DuckTales (1987) had Launchpad called in to a reenactment of a battle which his ancestor fought in (single-handedly costing his side victory). It turned out that some of the soldiers (now ancient) who Launchpad's ancestor lead to defeat are in the area, and draft him in a plan to win the reenacted battle and regain their honor.
Rocky and Bullwinkle ended up getting the Wassamatta U football team to reenact the Civil War on the football field - during the game. This somehow enabled them to win the game.
The New York City of Ugly Americans has an annual apocolypse reenactment, which is a cherished part of demon culture. In the episode it's featured in Lily thinks it's slipped into Not a Game but that's only because he didn't read the script.