I helped implement the concept of a "Sunday Supper" with our friend group in the city. It's basically held every Sunday and rotates to different households who feel like hosting that day. Luckily one person is sort of the "default" since their family's child situation makes it more convenient for them to host vs. go elsewhere.

It's basically an open invite for a group of friends, and a standing thing that just happens. If you have no other plans, you basically go. Sometimes I have to drag myself out of the house to do it - but it's worth it every time. The group that attends sometimes is just one other couple, sometimes it's a house full of 30 people if everyone comes, brings their kids, and a few friends of friends tag along.

Definitely one of the better things I've been involved in!