PREMISE
This game will be a game about a secret organization of paranormal investigators spread throughout the world investigating a phenomenon occurring in their region. The nature of the anomaly is poorly understood, and the organization researching it is attempting to keep the facts about it under wraps in collaboration with governments and corporations. The effects of the specific anomaly, however, occur at the same exact time at every location where researchers are stationed, although the effects can vary depending on the location.
MECHANICS
The game will be played exclusively over snail mail, with a single game master address acting as a central liaison for decisions and contributions made by individual players, as well as the final arbiter of what information contributed by players is determined "game canon" (through independently resolving any contradictions). However, this game will be primarily collaborative, and players have the option of communicating privately with one another via either mail or direct communication to determine what choices they make in response to the game master's missive and what sorts of material they send to the game master to communicate what's going on in their part of the world. The game master will compile an introductory packet and mail it to all of the players containing information about the state of the game world, the ongoing research into the anomaly, any events happening in the game world that will bear on people, as well as both closed- and open-ended facts and choices to make about what has happened to their own part of the world.
As an example of gameplay, a player might receive the same game state update that other players received, describing what has happened in other parts of the world that all players in the organization are meant to be privy to, as well as an additional letter or fictional news clipping from the GM describing an event that has suddenly happened in their region to respond to, or an open-ended choice such as: "Choose one: One of your projects has failed in a way that has cost lives -- what happened, and what has your institution done to address it? OR One of your organization's members has discovered a new fact that goes against the wishes of your superiors. What is this fact, and have they chosen to reveal it or conceal it?" Players will have broad powers to create new characters, organizations, and events in their region as they see fit, and the methods players may use to describe what happens are very numerous. For instance, a player might choose to send the GM a chatlog from two members of an organization discussing a discovery made at the site of the anomaly, or perhaps create a fictional news clipping (or even a real news clipping!) that bears on the project. With this in mind, however, the ultimate goal is not necessarily to "win," but instead to collaboratively create an engaging and interesting story.
The game will take place over a long time period. The GM will compile a packet of information for each player, some parts of it universal and some player-specific, and send it out to them, and players will then send back to the GM their own packet of information for the GM to integrate into the setting and use to compile the next missive of information in the collaborative storytelling. The next packet of information will be sent when the GM has received a reply from all players and has created the necessary reply. Obviously, this will not be a fast game, so it is a good idea to spend time crafting your reply and putting a lot of love into it.
It may be prudent, in case of postage issues, to also create digital copies of the material being sent in case it is necessary to email them to the GM; however, part of the appeal of this game format is that it is primarily physical, so this should be done only in the event that it becomes absolutely necessary. The GM will begin compiling and then sending out packets when they have received replies from everyone. However, if you feel that you will not be able to get to your message in a timely manner for that turn, you have the option of messaging the GM directly or through ooc-communication that you are passing that turn.
Clarifying errata: The sorts of stuff that you could send for your turn in the game could range from direct letters to the institution that's in charge, conversations between people in the location that you're in charge of, news clippings, polaroids of things in the location, it’s all up to you. Also, you're not only in charge of one character, although you could choose to have your contributions all be through the lens of one character — you can go as far as deciding events and people in the entire location you’re in control of. You do not necessarily need to be in control of the region where you are located; you could choose to locate your research institute and its surroundings anywhere in the world if you so desire!