The 80% Company
Nick Denton says in his article that a company where people do not work very long hours, only work 4 days a week (i.e. 80%) and "have a life besides their job" should be more efficient and productive. He claims that people work more disciplined and effective if they have to get everything done by 5:30pm, e.g. to relieve their kids from childcare. Secondly, they focus on getting their job done instead of "satisfying their psychological needs" through their job - meaning they are more flexible mentally regarding changes in their job, less interested in politics and endless fruitless discussions just to prove they were "right", etc.
It sounds convincing, however I'm not sure if it really works. Dave Winer believes it doesn't.