Pascal's Wager is an attempt to prove that believing in God is statistically in one's best interest. There are tons of other essays on it on this site so I'm not going to explain it, just address an interesting objections with some depth.
The "Anti-God" objection is essentially a claim from that we cannot know the true nature of God. Essentially, for all we know, God could be the opposite of what you think that he is. Instead of being "saved" for being a Christian and living a good life you would be damned. Essentially under an "anti-God" the quickest way to get to heaven would kicking puppies, mass murder, and stealing from charities.
Now, there are two ways to object to this:
1) Claim that an Anti-God involves some kind of paradox (this is pretty hard to do)
2) Claim that the possibility of an Anti-God doesn't nullify the argument
I think the second objection works pretty well, I would rather go to Hell and suffer forever with Mother Theresa, Ronald Reagan, John Paul II and all the rest of the awesome people of the world than chill in a pleasant heaven with a douche-bag God who enjoys kicking blind three legged puppies in their cancer filled ribcages.
Whatever, all I'm saying is that if you disagree with me, the next time you see a blind legless puppy trying to cross the street, kick it in the ribs...just in case