I am self motivated for the most part. Of course having a coach crack the whip now and then helps also.
I know that a lot of people will pay to motivate themselves...if you pay you will go so as to not waste your hard earned $$$. Same thing with personal trainers in gyms.
A good way to go about motivating yourself is to set goals. You have the big goal and then set a bunch of smaller, easier to attain goals to achieve along the way. In the martial arts (which I don't know a lot about) it may be reaching belt levels and then a competition.
During the summer I don't have any trouble geting out the door...its sunny and warm. During the winter it can be a lot more difficult...I don't like the cold (this winter has ben nice ecept a few weekends). But I know my Ironman is early in the season so I have to get out the door.