Is to let them work.
Yes! The majority of the companies are wasting lots of money on open office environment, fun parties, meetings and lavish conference rooms and so on and so forth but I think they are forgetting one important thing - give the developer a freedom to work.
Before you hit the downvote. Allow me to explain.
"Just shut up and let your devs concentrate" - Joel, CEO of StackOverflow.
I am not against the amazing facility of office, whether its fridge packed with food, gym or open office environment. I am against the fact that in making the workplace looks more lavish from outside we are putting away our focus from one important thing - concentration.
I am sure you guys have watched "The Social Network". There is one scene where the developer is "wired on" i.e working and wearing headphone and during that time he is not allowed OR no one else is allowed to interact with him. What's that for? Concentration.
Concentration is the key to productive work. We must design our office with a mixture of open office culture where there is lots of fun, abuses floating around in air along with a place where people can sit down, cut off from the rest of the work and concentrate. In my case and I am sure in lots of devs case, concentrate on solving the problem.