Running and playing in official play gives you a lot of that feeling. Running your own home brew open table does a little, although I didn't allow characters from other campaigns. It does take a lot of work to set up though.

I used the Alexandrian as a heavy inspiration. Recently I was re-digging through his older stuff, and found out where his inspiration had come from: remembering the way he used to play in school: https://thealexandrian.net/wordpress...our-game-table

I never played that way myself. I started in the 80s and it was considered far too nerdy, not enough people were willing to play. Instead all the pick-up games during breaks were Hearts.