Find something outside yourself to focus on. Some quotes:

>The more I reflect on this question, the more convinced I am that man's fundamental purpose is to achieve; in other words, the striving toward goals is an end in itself. ... Viewed in that light, it would seem that striving itself - the constant working toward goals - is man's real purpose.

- - Robert J Ringer, How You Can Find Happiness During the Collapse of Western Civilization

>In order to live free and happily, you must sacrifice boredom. It is not always an easy sacrifice.

- - fortune-cookie, no attribution

>The only true happiness comes from squandering ourselves for a purpose.

- - William Cowper

>To be of use in the world is the only way to be happy.

- - Hans Christian Anderson

>We act as though comfort and luxury were the chief requirements of life, when all that we need to make us happy is something to be enthusiastic about.

- - Charles Kingsley

And Eliezer's post on how having "Something to Protect" gives meaning to life, http://lesswrong.com/lw/nb/something_to_protect/

Something to protect is the most significant from your comment's view, fear of risk to your "something" is the strongest driver around.