I really do like the idea of making dull or costly activities fun - activities that have no apparent immediate or intrinsic reward for the individual performing them (the laundry, tax forms and toenail-clipping are my prime candidates). This is the idea behind The Fun Theory, an environmentally-oriented VW award scheme in Sweden. It's the carrot rather than the stick.
Fun has its limits, of course - ethical, psychological, economic (Making your choice of political candidate fun? Making long surgeries fun for the anaesthetists? Making volunteering for the military fun? hmm...).
Having said that, is there something worth considering in taking fun more seriously at work? If you look at what fun means in the Fun Theory context, it represents an experience of some immediate (and quite transient) emotional pleasure based on a kind of competitive gratification (winning a game or a lottery) which engages attention and effort for a short period of time.
How could this be applied to otherwise dull jobs (where perhaps the performers will supply their own fun distractions)? I'm not sure one can sustain attention with this kind of fun for very long - but it would be interesting to try applying it in situations where some intermittent or short attention is needed to otherwise boring or ignored tasks (hand-washing in hospitals?).
Fun has larger meanings in a work context. There are 'fun' companies with game consoles and foosball tables de rigueur, and those organisations with more conventional sports and social activities, to foster relationships and 'culture'. And there are those who take 'fun' even more seriously, by looking at what fun work might really be about - the intrinsic needs of humans to be productive, creative, involved and recognised. That kind of fun is often harder - less fun? - to allow or enable, but puts other kinds of fun into perspective.