Boring + Boring = Pleasant?!

I've read that Aristotle taught his students while they walked around. It seemed to enhance learning and make the activity more enjoyable. The self-experimenter Seth Roberts has found that doing two boring things together -- walking on a treadmill and studying flash cards -- results in a pleasant experience.
Fact 1: For the last few weeks, I’ve been studying Chinese using a flashcard program called Anki. It’s an excellent program but boring. I’ve never liked studying – maybe no one does. Fact 2: I’ve had a treadmill for a very long time. Walking on a treadmill is boring so I always combine it with something pleasant – like watching American Idol. That makes it bearable. I don’t think listening to music would be enough.

Two days ago I discovered something that stunned me: Using Anki WHILE walking on my treadmill was enjoyable. I easily did it for an hour and the next day (yesterday) did it for an hour again. The time goes by quickly. Two boring activities, done together, became pleasant. Anki alone I can do maybe ten minutes. Treadmill alone I can do only a few minutes before I want to stop. In both cases I’d have to be pushed to do it at all. Yet the combination I want to do; 60 minutes feels like a good length of time.

His thoughts on why this might be so are really interesting:

The evolutionary reason for this might be to push people to walk in new places (which provide something to learn) rather than old places (which don’t). To push them to explore. David Owen noticed it was much more fun  for both him and his small daughter to walk in the city than in the country. He was surprised. When I drive somewhere, and am not listening to a book or something, I prefer a new route over a familiar one. If I am listening to a book I prefer the familiar route because it makes it easier to understand the book.
Boring + Boring = Pleasant?!