"God cannot be proven" - The atheist logical fallacy
God has already been proven and in a number of ways. Perhaps the most compelling of which is the creation argument. Why do we have something rather than nothing? That question cannot be answered without first disregarding our most basic laws of physics. Essentially, only a God like being (or act) could get us a universe from nothing.
And there you have it: proof of God. Now watch as atheists continue to deny God even as the proof sits right in front of them.
I'd like to point out that it is moronic to argue with someone who has faith. Faith means you won't listen to reason or accept evidence. The difference between most atheists and most people of faith is that if you show me proof that something I believe is wrong then my beliefs will change with the facts. No amount of proof can change the beliefs of someone whose only answer is faith. Faith is the worst thing that has ever happened to human progress. Faith tells you not to ask questions or use your rational mind to observe the world around you and make your own conclusions. Faith is scientific ignorance that only panders to weak minds.