pre XP experience
In the mid 70s I was a member of a team of about 30 developers in a telecommunication project. We had old fashioned offices with 2 to 4 persons per room. There was a 15 to 30 minutes coffee break twice a day quasi mandatory for everyone in a large room with one big table which we also used for meetings and around which everyone could sit. You wouldn't believe how much "osmotic communication" (of course no such term was coined at this time) was going on there, so much that afterwards we called our overall design and development method "design by coffee table". The system never went into production for political reasons despite the fact that we successfully proved it's viability.