Just look around. The meaning of it all is there, around and inside you.

Nature's creations live their life according to two simple states: suffering and joy. Human and animals alike are living on a scale which has suffering on one edge and joy on the other - no matter wether this life is driven by instinct or consciousness.
Now look at the laws of nature which are written down in physics and mathematics. They clearly show you that no extremes can last and that the state of the world is waving through time. Force is followed by an opposite force, increasing followed by decay, positive by negative - everything is moving and waving directly towards one extreme and then towards the other, without ever reaching one of them, or without ever reaching an optimal state. This is how the giant planets and stars move, but this is also how the tiny particles, the atoms and the electrons behave.
Just imagine what this means in life. No extreme may be strong enough to survive - even extreme joy may kill you. Life itself is a natural flow of gain and loss, in which your task is to find the balance between the extremes - to find as perfect balance as possible. This balance is called happiness, and this happiness is called the meaning of life.
The hard thing is that technically we should live our life pursuing an optimum of emotions in an eternally changing environment that itself never reaches balance. The laws of nature tell us clearly that our life can never be balanced perfectly, however, we always have to seek for this unreachable balance because only this can give a meaning to life.
And what if the meaning of life wouldn't be happiness at all? Well, would you be able to find a meaning in a life that you would hate to live because you don't find happiness in it? As a matter of fact, people usually don't look for the meaning of life - they just look for something that makes them happy, and they call this something the meaning of their life :)

As you see the meaning of something is in it's processes - as it 'behaves' through physical interaction with it's environment. But this meaning only comes into existence when this behavior interacts with a consciousnes that observes it - i.e. your mind. So the one that gives the actual meaning to something is you. Therefore the meaning of life or the meaning of anything in existence is whatever you say it is.

So what really makes me wonder is not what the meaning of life is. What really makes me wonder is the purpose of existence and consciousness - if there is any. Beacuse without a purpose you can do whatever you want. But if there is an ultimate purpose in this whole thing then there must be something ultimate and eternal. And of course, there is such thing... But that's another story... :)