I know of a startup that does group lunch every day. Even the remote people join (through Hangouts). I found it pleasant... It strengthens the team _and_ forces everyone to take their eyes away from a screen, slow down, and get out of the weeds. They go on a group hike every afternoon for the same reason.
I don't know how long they'll be able to keep it up as they grow, but I thought it was great.
I don't know how long they'll be able to keep it up as they grow, but I thought it was great.