One-Shot Theater is the pet name of the #besm folks for their one-shots: short, mini-campaigns or sessions. They're often ways for characters from different universes to intermingle and GMs to test their mettle or just kick back and run a silly idea they had in the shower once. The idea is it's a one-shot, so planning for an entire campaign need not be based on it. Usually done in BESM, this page can host one-shots from other systems, too, provided they're on sandwich.net.

One-Shot Theatre: Part 1 Part 2 Part 3 (Demonic High School)
Gamemaster: Yu-Mei
Player Characters
Misa (Engines and Dragons)
Atsuko (SMF^2 - second run rules)
Miako (SMF^2)
Miya (BESM Arena - rules)
Eui-Tae (Planeteers 2076)
Fyril (Age of Chibi)
Saki (Two Sides of a Coin)

Big Brother's Theater (George Orwell Theater)
Gamemasters: Ardweden and Zegon
Player Characters
Chelsea (Mystery Club)
Lisa (ATC)
Chie (Mystery Club 2)
Asa (GCI)
Saki (Two Sides of a Coin)
Gwen (Sky Pirates!)
Ichi (El WHAT?!)
Daegal (X-Pialadocious)

Adventures in Anachronisms (Modern Day Fair)
Gamemaster: Ciara
Player Characters
Taki (Arcana)
Kyle (Miskatonic High)
Lurika (Kaminari no Shimei)
Irwin (Rising Sun Pioneers - rules)
Ao-Lang (Battle High)
Claire (X-Pialadocious)

Three Ladies and an Alien (Science Fiction Fantasy)
Gamemaster: Jex
Player Characters
Taluun'tzo (ATC)
Millie (Rising Sun Pioneers)
Chie (Mystery Club 2)
Taki (Arcana)

Cast Away (Renaissance Pirates)
Gamemaster: Rowyn
Player Characters
Ryuhi (NeoEarth)
In'You (Rising Sun Pioneers - rules)
Saki (Two Sides of a Coin)

One-Shot Babies (Modern Day Care)
Gamemaster: Ardweden
Player Characters
Eric (Otherworld 2)
Kyle (Miskatonic High)
In'You (Rising Sun Pioneers - rules)
Thalan (DragonStar - converted)
Ichi (El WHAT?!)
Victor (N/A)

Future Imperfect Telepathic Talks (Far Future)
Gamemaster: Jex
Player Characters
Eric (X-Pialadocious)
Daegal (X-Pialadocious)
Katie (Arcana)
Satoshi (Arcana)
Haruko (Arcana)
Maria (Mystery Club 2)

Steam and Punk Eliana and Angel Not-Murder The Lounge (Tri-Stat d6 - Victorian Steampunk)
Gamemaster: Grysar
Player Characters
All characters were designed for this game.

Why does everybody want our rock? (Far Future)
Continued coverage in this setting here.
Gamemaster: Grysar
Player Characters
Thalan (DragonStar - converted)
Murynal (Space Opera)
Neisis (The City - rules)

No, Mr. Bond. I want you to be an adorable souvenir. (Tri-Stat d8 - Modern Day Supernatural)
Continued coverage in this setting here.
Gamemaster: Grysar
Player Characters
All characters were designed for this game.

The Moogle and the Anvil (Anvil)
Gamemaster: Brett
Player Characters
Mogin (N/A)

The Yellow Turban Fortress (Dynasty Warriors)
Gamemaster: Brett
Player Characters
Mogin (N/A)
Rina (GCI)
Jinx (Rising Sun Pioneers)
Naoki (Rising Sun Pioneers - rules)
Spirited (N/A)

Yet Another 'Save The Universe' Scam Group The Second (Science Fiction)
Gamemaster: Segev
Player Characters
Claire (That Game)
Chie (Mystery Club 2)
Maria (Mystery Club 2)
Rei (Mystery Club 2)
Thalan (DragonStar - converted)
Katherine (ATC2)
Kaede (Arcana)

.crack//COW (Online RPG)
Gamemaster: Jex
Player Characters
Maelstrom (SAB 2020)
NoraNeko (Animon)
Atrim (Vermillion Ideals - rules)

The Bouncers (Bizarre Nightclub)
Gamemaster: Jex
Player Characters
Arry (Sky Pirates!)
Lurika (Kaminari no Shimei)
Keika (Death Blossoms)

The Game With No Name (Fantasy)
Continued coverage in this setting here.
Gamemaster: Mechalink
Player Characters
Arisa (N/A)
Taki (Arcana)

As Primitive As Can Be (Desert Island)
Gamemaster: Brett
Player Characters
Keika (Death Blossoms)
Kiku (Death Blossoms)
Hilde (Death Blossoms)
Menchi (Excel Saga)

Toast! (Modern Hospital Mystery)
1. The Inmates... A Map
2. A Question of Commitment
3. That Hath Such People In It
4. In Which Young Miss Yoritomi Behaves in a Most Unladylike Manner The Letter The Note
5. I've Got a Theo-ry
Gamemaster: Nicolas
Player Characters
Eui-Tae (Planeteers 2076)
Miya (X-Pialadocious)
Terry (Yu-Gi-WHAT?!)
Theodore (Otherworld Revised)

Saving the Worlds that Sanity Forgot (Tri-Stat d8 - Surreal Science Fiction/Fantasy)
Gamemaster: Sharyna
Player Characters
Kirie Sakamoto (N/A)
Sayura (Section M - rules)
Telion Salamander (N/A)
Ten (Mystery Club 3)