An interesting piece in May’s The Atlantic Monthly featured a piece on Melvin Konner’s new book: http://www.theatlantic.com/magazine/archive/2010/05/play-8217-s-the-thing/8028/
This tome (900 pages) focuses on the idea that the smartest species are also the most playful. Play is tied to growth, discovery, learning and new skill development; thus, says Konner, play is critical to survival of the fittest.
As an improviser who applies improvisational exercises and play in the workplace, there is no question that play and discovery are critical to innovation. Play is absolutely Darwinian in that it is the impetus for organizational survival through learning and evolution.