In addition to some great answers here, my team setup a “Live Window” in our San Francisco and New York offices.

The live window is a big TV with a webcam that is constantly streaming live video to the other office. It gives us the opportunity for those “water fountain” conversations with team members we don’t normally see on a day-to-day basis. New haircut? New outfit? I would have never known!

It feels a bit creepy at first but after a week or two, everyone warmed up to it and we feel more closer and more integrated as a distributed team.