How do you motivate yourself?

It's an earnest question, and I'm not interested solely so I can poach your great techniques. I'm interested because ever since my father strapped my brother into his seat so that he might be motivated to finish his dinner, I've been fascinated by what what really inspires people to finish the work in front of them--especially if these methods are extreme. An Ohio State University study on employee motivation broke down the importance of the following factors:

The ranked order of motivating factors were: (a) interesting work, (b) good wages, (c) full appreciation of work done, (d) job security, (e) good working conditions, (f) promotions and growth in the organization, (g) feeling of being in on things, (h) personal loyalty to employees, (i) tactful discipline, and (j) sympathetic help with personal problems.

Motivation in your 9-5 is one thing, but how do you motivate yourself to pursue extracurricular passions (writing, exercising, calling people back, cleaning, cooking, anything) after you clock out? Edmund Wilson used to lock Mary McCarthy in a closet with a typewriter. I have chasmophilia, so this relationship seems ideal to me. There's just something unusually comforting about small spaces; I always prefer the smaller room in apartments I've had, and when I drive I like to be inches from the wheel. And when I have writing to do, sometimes there's no better place to do it than the backseat of a car, or at least a tightly packed bus with little leg room. But I'm weird. What about you--what that motivates you?