I recently participated in a LinkedIn conversation asking this question. It was the longest running thread I have ever seen! What was interesting is that so many people had very different views. Most felt that fun can motivate people into being more productive whilst some were firmly of the view that work is a place to get your head down, and fun should not be a word we associate with work. Lots of people contributed with their own definitions of fun and with examples of things that they had experienced.
I recently attended an event and heard a presentation from Catherine Wilks of company called Inmovement, they specialise in playground sessions for the business workplace. I was out of my comfort zone really, as lawyers we are used to being quite serious. Catherine had us participating in activities which involved moving around the room and yes, having some fun! It got me thinking about how we should all try to incorporate some fun and creativity in our workplaces, by doing that you get something different back from those that work around you. Catherine explains her principles on this link Play for Engagement - Inmovement.
and not this sort of fun.
A recent case by a 36 year old telesales worker, Petrina Taylor, against BT cost them £290,000!