By Todd Bernhard
Apple is building a major "spaceship" campus in Cupertino, but other Silicon Valley companies already have some offices that are pretty far out. Facebook and Google have campuses that make you wonder how any work gets done. In fact, if you watch Silicon Valley on HBO or Last Man on Earth on Fox, you get a glimpse of the fun environment many Silicon Valley startups and heavy hitters try to offer their employees. It's all about retention, since it's more expensive to find new talent than it is to keep it.