There may be no purpose, but it is always good to have a mission... At the end of The Eagle's Gift, Don Juan reveals to his student that there's no point to existence. That we're given our brief 70-100 years of consciousness by something the mystics call "The Eagle," named for it's cold, killer demeanor. And when we die, the eagle gobbles our consciousness right back up again.
He explains that the mystics, to give thanks to the eagle for the brief bout of consciousness they're granted, attempt to widen their consciousness as much as possible. This provides a particularly delicious meal for the eagle when it gobbles one up at the end of one's life.
And that, to me, is a fine mission.
-- Adam Savage, Delivered to the Harvard Humanist Society, April 2010, http://www.boingboing.net/features/savage.html