Manufacturing Interest - part 1

I've been reading a lot lately about 'Interest Based Learning' as part of my Learning Creative Learning course. The general premise of Interest Based Learning is that you use a childs interests as a way to explore and learn and connect other learning in to their own model/view of the world. It is very inspiring to someone who dreams of never hearing a student say they 'hate maths' or 'when will I use this, sir?'.


One problem that is niggling away at me about this though, is that teenagers don't seem to have any interests. As a teenager, I was interested in very, very little. Pretty much everything I did could be boiled down to five motivating factors:

1. Bodily needs - Hunger, tiredness, etc.
2. It was expected of me (by parents or elders) - e.g. This is why I went to college and university.
3. Shortest/Easiest path - I spent my teenhood in a state of eternal tiredness. Most of the things in my life were something to 'get through' before I could have a nap.
4. Respect/notice of peers (and/or attractiveness to girls) - e.g. Acting the fool, playing football, pretending to be happy.
5. Distraction from life.

Left to my own devices, I would not have known what to do with myself, and probably would have spent those years playing computer games and sleeping.

(Note that the two that would lead me to learn most of the things I learnt during school (2 and 4) are extrinsic motivators.) 


Now from this small set of things, that pupils are interested in, there is a much smaller subset of things that I am knowledgeable enough about to bring in to lessons. I have successfully brought in computer games (e.g. Kill/Death ratios used in Call of Duty), art and some sports. That's as many as I've been able to find so far.


So how do you use a person's interests to help them to learn when they don't yet have any interests? How do you foster someone's interest in something without extrinsic motivation? How much of a teacher's time should be spent 'marketing' their subject and 'generating interest'?