Open window in the main area with a fan pointing out. Windows partly open in other parts of the house, trying to balance the airflow so as much air as possible traveled past the guests. I preheated the house earlier in the day, and during the event had the heat on maximum. It was a bit chilly near the end, but still tolerable.

Air purifier cubes in each room.

In the main area, which isn't a good fit for one, I made a bit of a tunnel above the bookcase.

Masks on, except when eating. People were good about this; I didn't see people hanging out with mask off and a plate but not eating.

Rapid testing at the door ($7/person). We lined up a volunteer to handle this, because Julia was dealing with hosting and I was watching the kids upstairs. With each test they wrote down the person's name, the time where it needed to be read and their cellphone number. When each test had been sitting for 15 minutes, we texted the person the result. We asked people not to take their mask off to eat until they had their results. If any tests had been positive, we would have informed the group. False positive rate is ~0.05%. We are keeping the cell phone numbers for a few days, so we will be able to text everyone if anyone later notifies us they have it.

We told people vaccination was required, though not boosters. We intended to check vaccination cards (accepting photos) at the door, but forgot. If I was organizing something like this a few weeks from now, when there has been more time for people to get boosters, I might require them.

We considered requiring masks to be surgical or better (offering free ones) but decided not to. I think this probably would have been worth doing, except that we added several of these precautions after announcing the gathering, and it felt like too much to add another one.

Occasional crowd management, encouraging people to move from denser spaces to emptier ones