Aw, man. I wish there were an "I'd rather not know" option. I'd so pick that one.
Anyways. As most of you have predicted, "purpose" is quite the human thing. So human, in fact, that we have troubles defining our personal search for meaning as a word. (Pssst! The current word is "Spirituality").
I firmly believe in science, and as a consequence, in Science Fiction. As such, i believe that in due time, things like Time Travel, Space Travel, Body Alteration and Limitless Energy will happen. In fact, some of those are already in the making! Maybe you and i will live enough to see one of those. Maybe you or i will be the ones to CREATE one of those. Whatever the point is, i'd like to share an anecdote i was thinking about earlier today, just by chance.
A few years ago i read "The End of Eternity" by Isaac Asimov. It's a cute story, deals with tons of time travel and is quite useful to define some concepts in science fiction. I'd even go as far as calling it a "deconstruction" of the time-traveling genre, dealing with not only key issues in time travel, but also in its dichotomy (in Asimov's oeuvre, mostly) with space travel. Point in case is (this is sort of a spoiler so i'll skip the why) it got me thinking about how most things deeply involved with time traveling end up being their own cause/purpose/raison d'etre. So why not apply this to the Universe?
Say eventually, in year 1400 AM (After Mortality, just a cute calendar i'm creating because i've just answered this question), someone figures out time travel. All's dandy, the world doesn't ends because of some teenage prank, and eventually the technology becomes... not quite widespread, but not a secret anymore. I'd bet money on eventually, humans would give the universe and/or life meaning, if only because they can.
How? No idea.
Why? Beats me.
The fact is, if humans can, they WILL.