Similar to what James mentioned, at my last employer we played Capture the Flag Quake. My co-workers and I formed a 'clan' and hosted a server where we would play LAN party style over lunch and then take on other, outside clans in matches after hours. Engineers, technicians, and managers were all team mates looking for frags, it was great.

CTF forces teamwork and an "I got your back" attitude and this mindset carried over directly to our projects.

Sometimes, names disappeared in emails and we referred to each other by our avatar's alias.