wfz on 01 February 2013
To reproduce and continue the search for understanding our universe and gaining more control over it.
Or, if our universe is some sort of experiment, then our purpose is to do whatever we naturally desire to do so our creators can observe what we and the rest of the life in the universe do. In this case, our purpose is the same as my first sentence, since reproducing and continuing our advancement as a species is something we naturally strive for.
