Work or Play? What's the Difference?

According to Tom Sawyer, there's not much difference between work and play.  Work is what you get paid to do, and play is what you pay to do.  This definition makes sense to me.
Back in the nineties, my husband and I frequented a mall with a lot of escalators.  As we rode one of the escalators, we could see people working out at the gym on step machines.  People paid to "take the stairs" in a gym, but most were unwilling to take the stairs for free in the mall.  Taking the stairs was work.  Paying to use the step machine was play--or at least exercise. 

For me, work also includes things I "have to do," such as making dinner.  When I was a teenager, cooking was fun.  Now that I do it every day, it's work.  Actually, a lot of things I used to consider play have--without my realizing it--passed over to the work category.  I don't want it to be that way.  And I especially don't want my current playtime activities--like my writing--to turn into work.

Wouldn't it be great if we could turn our work back into play?  How do we do that?  I know part of it is our attitude, but I think we can also do things to help turn our work back into play.  Trying something new, adding fun music, listening to audiobooks while working, and working with other people all make my work more enjoyable.  What helps you turn your work into play?