Some of the things gopher mentioned, I do consider to be obligations.
Many books on the market have been written with the philosophy of how to change work into play by simply tweaking your thought processes. By involving yourself in your work; such as challenging yourself, finding ways to invoke your curiosity, integrating your interests, setting goals for success, etc. one individual can easily make play out of an activity that another individual might consider work. So obviously, I wouldn't expect gopher and I would consider all the same activities to be work.