Perhaps the most fascinating aspect of Hinduism is the idea of reincarnation. In this age of corporate yoga and pharmaceutical Buddhism there's hardly a person who can't expound on how we're all stuck in samsara, the eternal wheel of reincarnation, our souls endlessly striving towards final liberation or moksha. But other than philosophical fancy or fodder for stoned wonderment, what does reincarnation actually entail?
I found my high school adviser's metaphor to be quite helpful. We are all familiar with the sight of bubbles rising out of a carbonated drink. If we abandon for a moment our knowledge of chemistry, then it would seem that air emerges out of nothing, forms bubbles, and rises to the surface, dissolving into the atmosphere. In the same way, our souls (atman) are small pieces of the stuff of eternity (Brahman), like bubbles are of air. Our little 'divine sparks' are stuck in this world, like the air in the drink, but we also inevitably rise towards liberation. The bubble itself is the shell we create to shield ourselves from the nasty world- our egos.
That's all good and fine, but what does it mean for a strict materialist who doesn't want to concede all this 'eternity' and 'soul' jazz? I look at it this way. There's no need to invoke higher powers when you put your life up against the 6 billion others that are being lived right now (to say nothing of non-humans): the idea of that much humanity is eternal enough. The concession that your life is made up of the same stuff as anyone else's is tantamount to the idea that you could be born in any other life. The self-aggrandizing ego convinces us that we are 'lucky' to lead good lives, but really we're just monkeys with an attitude just like everyone else. And what goes around comes around.
Perhaps not the most elegant theory, but it gets across the same point. As Red Green would say: I'm pulling for you, cause remember, we're all in this together.