Making things fun to do - wouldn't this be great?

I ran across this video awhile back and think it's awesome. I used to ride the metro an hour each way to work in DC, having to climb the stairs or the escalator. It was often either depressing or exciting to be a part of the mob doing the same routine everyday. It would have been awesome if it could have been made fun!

This video was made by www.thefuntheory.com, who believe that the easiest way to change people's behavior for the better is by making it fun to do - that's why they call it the fun theory. Here is them testing it out.

I think this theory can be seen in so many examples in life, from teaching children to learning in the classroom to teambuilding to relationships. What do you think?