There is no real meaning to life. We all make our own meaning, which are made validated and meaningful by the people around us.
Even in the religious contexts there is no real meaning to life. God created the universe, put us all on this planet, and let us go at it. And if you follow some standards that some God who would be infinitely above to hold us to you can go to Heaven.
The real question you should be asking is "What is God's motive in our existence?" In the case there is a God, we were created here, and let to go at it, but for what? We run around on this planet our entire life span (which in the cosmic time scale, is less than even a second,) then die, and depending on your religious convictions, go on to do it all over again, simply cease to exist, or go to Heaven or Hell, or whatever you believe in. So, our time on this planet doesn't really matter to much, since we go on to do whatever it is in the after life.
Heaven doesn't seem to serve any real purpose. We're sitting up there, chilling out for eternity, doing God knows what. But people are happy, which is alright. Hell isn't productive. People getting sent to burn and get tortured for eternity doesn't really do much good. It's not like you just have to serve out a 20 year sentence in Hell. Even the American justice system isn't that bad. We're not sentencing people to eternity in Hell for not believing something in which there is great evidence for the contrary.
Anyway, the only real reason any of the religious contexts would be viable for a supreme being is if this God gained some sort of power from the praise, acknowledgment, and worship of people. And when we die, we go to Heaven, and act as God's eternal power source, and if you didn't believe, you go to Hell, which isn't exactly fair, but God is pretty malevolent in the Abrahamic religions anyway.
Other than that, maybe God was just bored. God seemed to be pretty fine before we were here anyway.