It's a bit of a shuffle, it's a bit competitive, and the whole thing has some Soylent Green vibes, but you can walk away from it with a bag full of usable groceries, and you don't need to give them anything. They're asking for a donation. It's not clear whether they'd turn a person away if they didn't have any money. There doesn't seem to be any minimum donation or maximum total items or anything like that. Some stuff has a limit, other stuff doesn't.
The format is: a bunch of boxes laid out on the sidewalk, with people supervising a line of recipients who proceed through the line of boxes, taking what they need.
It happens every Thursday at 4pm. It's unclear when it'll stop and then start up again, so it's not going in the calendar yet.