The startup community has been widely regarded as a "fun" place to work - from Threadless' warehouse parties with awesome bands and it's own brand of microbrew beer to Google's rooftop terraces and bowling alleys. So the question must be asked, why are they doing it, and how does it make them successful?
"Corporate Culture" - The word has been in the corporate jargon book since the early 80's but what it looks like now is much different than how it looked back then. In the 80's having a good culture meant having a big office on the top of an important building in Manhattan or throwing lavish parties in highly visible places or having big presentations about having fun at work (note: the presentations lead very little to having much actual fun at work) and most of the "culture" was happening at the executive level.
Today, at least in the startup community, it's been flipped. Corporate culture is much more internal and focused on the employees at every level. Corporate culture goes from having flex time (the ability to work from home part time) to having a very short corporate ladder where the CEO is still seen often and you, as an employee, can contact that person. It's about having daily or weekly rituals that really give the company a sense of identity or having a shower at work so you can bike to the office. It is all a part of making your company fit the values of your employees.
But that still doesn't answer why it's important to have a good culture. It's true that having a bowling alley at the office doesn't necessarily make the company money but what it does is aid in employee retention. The idea that if you make a company fun and challenging to work for, and if you make the company culture fit with employee's personal culture employees will hang around longer - which is a money saver. It is said that hiring a new employee costs about 150% of that employees first year of salary, this includes training costs, hiring cost, HR costs etc. It cost a lot of money to fire/hire someone so it's better to keep your employees happy. This, however, is only part of how corporate culture makes companies successful.
Remember your worst employer and your favorite employer - how did you work for each of them? How invested in your work were you? Were you excited to go to work? This is where the real success lies. The more a company can make their corporate culture align with their employees personal culture the closer they get to really maximizing the efforts of each of their employees. Sure it takes time out of the day to bowl a few frames but that employee wants to make the company successful and doesn't want to lose their awesome job - so they'll make appropriate decisions, it makes sense.