Pascal's position seems to be essentially this:
    By faith, one can know God's existence.  But why should anyone have faith or believe that God exists?
    To answer the question, consider the possibilities:
 
 

Pascal's Wager	You believe God exists	You don't believe God exists
God Exists	Eternal happiness, fellowship, hope=GAIN	Lose eternal happiness, lose fellowship of others, lose hope = LOSE
God does not Exist	Happiness in this life, fellowship, hope = GAIN	No fellowship, no hope = LOSE

The upshot of Pascal's position seems to be that no matter what, even if there is no God, you win if you believe - and so your best bet is to bet on the existence of God because it improves things for you in this life even if there is no God, and if there is, there is an eternity of joy to be gained.

Some Critical Points for Pascal's Wager:

1.  Does belief in God guarantee eternal happiness?
2.  Does disbelief guarantee that there is no afterlife?
3.  Is it the case that people who do not believe in the existence of God have no hope?
4.  IF THERE IS NO GOD, then isn't it possible that you have WASTED the ONLY life you have?
5.  Does Pascal's position seem to indicate that it makes no difference "which God" one believes in?  Or is "any old god" a good enough bet?
6.  Would God reward a believer who believes based on the wager?
7.  Some would say that if they base their lives on belief in the existence of a God and there is not one, then their lives have been a lie; others say that if they base their lives on DISBELIEF in the existence of God and there is one, then their lives have been based on a lie, anyway.  Which is the better case?
8.  Pascal grants that there are no fool-proof proofs for God's existence.  Doesn't this mean that a person who believes in the absence of good reasons has shirked his "epistemic obligations"?  Is this more important than moral obligations?  Are epistemic and moral obligations of equal importance?
9.  Some religions require martyrdom of a least some believers.  Are you willing on the basis of a BET to martyr yourself?  Even if you are not required to make exceptionally great sacrifices, what if your religion requires you always to be ready to do so?  Wouldn't this put a bit of a damper on THIS life?