I associate the term "Downtime Activites" with D&D 5th Edition, but Dave Arneson actually included a bunch of ideas fr what adventurers do between adventures in the First Fantasy Campaign (1977). BECMI also has quite a range of options. This came up in Cthulhudrew's thread about Weapon Mastery Rules and what other players can do while they wait for one PC to do some extra training.
Here are some ideas:
Downtime Activities in BECMI
by HåvardAT LOWER LEVELS
- Weapon Mastery Training
- Taking a job: The General Skill or the Specialist price list can be used to see what a PC might earn depending on his qualifications. There might be Guilds demanding membership in order to work in certain fields. Just basic manual labour might be enough to pay for basic living conditions.
- Gathering information: PCs could do research in a library, listen to talk in bars or elsewhere to learn about nearby dungeons, find out more about the plans of villains or perhaps learn new ways to fight certain monsters or how to survive in certain places.
- Carousing: If the PCs have gold to spend, why not spend a few weeks in bars, meeting members of the opposite sex, getting into a few brawls etc? Most adventurers need to unwind a bit between exploring dungeons and other dangerous areas.
- Persuing a hobby: As with carousing, some PCs might prefer persuing an art, read books or some other activity
- Prayers, fasting and attonement: As with hobby. In some cases, it might be required by the character's Immortal
- Petty crime: Thieves should be able to cover their expenses by using their skills, just like a Blacksmith will with his skills.
AT HIGHER LEVELS
- Spell research
- creating magical items
- Building a stronghold
- Dominion Rulership (See RC for a range of activities)