The only things I've heard about Facebook's office, from Facebook employees, is the constant, ongoing battle to keep people from playing noisy games during work hours.
I used to work there and my team was unfortunate enough to get relocated to a set of desks near a ping pong table during a floor reshuffle. It was noisy, infuriating and a huge distraction. The ping pong noise itself was nothing compared to the shouting, cheering and the noise of the ball inevitably bouncing away across the floor with someone running after it every 30 seconds.
A colleague put in a facilities ticket on the morning of the second day we were there to get the table relocated. Facilities couldn't find anywhere else to put it (because it would've meant simply disrupting someone else's area) and so the table was removed and put into storage. This caused a huge outcry from the ping pong players, but did have the upside of allowing us as developers to do our jobs.
I saw the whole situation as quite ridiculous, given that we were all at work in a company office and getting paid to code rather than to play ping pong. The counter-argument was that the removal of a ping pong table was the thin end of the wedge and the sign that FB was slowly becoming corporate and losing its hacker soul. I guess I can see the point, but the reality is that ping pong is a brilliant game until you have to sit near the table and try to work.
The ping pong table has become a battleground.