No formal block parties, but if I'm at the BBQ, and my neighbors are walking in/out of the house, they get offered a beer/wine/soda/juice as appropriate, and they do the same - I probably spend as much time sitting at the table in my neighbors yard watching my son and his daughter, as I do in mine. No excuse for an informal party needed other than "The weather is nice, and we are outdoors". Everyone will stop and at least wave hello

Now - here is the kicker... I live in New York City!!! No, not Manhattan, but Queens