The idea I'm most fond of is that the meaning of life is to observe the universe, itself.

Think about it: what good is the miraculous occurrence of a big bang, the accumulation of matter to make stars, planets, and galaxies, the happenstance of an asteroid hitting our home rock which was positioned just the right distance from its star, creating a moon, which created tides, aiding in abiogenesis (the inception of life)? What good is any of that if no one is around to observe it and try to understand it?

The meaning of life is that we are the universe trying to understand itself. We exist to observe the marvel of the vastness of our universe for the little time that we have before it all collapses back into the singularity (as it were) from whence everything came.