Here's one example of fun: My partner likes to watch a couple of TV shows that I have little or no interest in. I like to be tied up. So, I end up occasionally watching some show (or simply listening, since I'm usually blindfolded!) and she gets companionship that she'd miss out on otherwise.

It's one of those "learned response" things I guess, when seeing something queued up on the Tivo causes arousal. :-)