YAOSC (Yet Another Old School Clone)
YAOSC is designed with a common “default setting” in mind — a fantasy world with multiple intelligent species, technology levels approximating that of Classical or early Medieval Earth, moderately controllable supernatural forces, active deities, monstrous creatures to battle against, and the ruins of lost civilizations to explore in. The world is assumed to have generally Earthlike gravity, weather, annual and diurnal cycles, etc.
However, YAMs are encouraged to create and, over time, add detail to home-brew settings. These settings may begin as broad outlines or a handful of house rules. As a campaign progresses, YAMs are encouraged to continue building. Below are a few elements that can benefit from consideration. Note that the list is necessary incomplete and non-binding, and YAMs can benefit from inspiration from many sources, including other players. Why not let players with priest characters propose some holy days and ritual feasts or fasts? Why not let any player develop a character’s home town, family tree, guild, etc?
A campaign-setting calendar can be as simple as a real-world calendar with in-world events penciled in on it, or as complex as an alien almanac for a world with multiple moons and suns — every group will have its own preferred balance between novelty and ease of use. No matter what you go with, though, generating a campaign calendar offers benefits in three areas: planning, record-keeping, and verisimilitude.
First, a calendar is invaluable in planning out events in advance. Noting a lunar cycle helps track the activity of werewolves and other supernatural beings. A horoscope with ascendant planets could influence arcane activity. A calendar can be filled with festivals, ceremonies, and other events for the PCs to participate in or disrupt. Calendars remind you when the seasons will change, when a volcano will erupt, when a war is going to start, when the goblins plan to begin their raids, when the stars will align and release the sleeper from the deeps, and so on for any event you hope to throw at the PCs.
Second, a calendar persists even after the days on it have passed; this can be a handy space for keeping track of time spent engaged in social activities or in recovery after an adventure. Even more importantly, it can become a record of campaign events — a history in addition to a planning tool.
And finally, a set calendar gives a sense of a larger world going on around the events of the campaign, especially when a long time is passing in the game world. Changing seasons, recurring holidays, background events that the characters hear about even if they never get involved, and so on all help to build a feeling that the world they are adventuring is dynamic and alive.
It’s sensible to start with a limited amount of mapping done — you might start with a world or regional map just to have an idea of how the setting is put together. But all you need for adventuring is a single dungeon or area map, and there’s nothing quite like having adventurers on the ground to help you overcome inertia and start creating.
As a campaign continues, just as you should update the calendar with new ideas, so should you continue mapping and adding details to existing maps. Unless the campaign centers around a megadungeon (and often even then), players will be interested in exploring an increasingly wide area as a campaign progresses.