For God to prove himself on demand, physically, would be a grave disappointment, and the strongest Christians should be considerably grateful that he chooses not to do so. The skeptic endlessly demands proof, yet God refuses to insult the true intelligence of man, the '6th sense', the chief quality, the acumen which distinguishes man from the rest of creation, faith.
Of all the major religions, or lack thereof, the atheist's is one of the best pretenders: his foundation for all existences, as well as moral behaviors for the permanent good of mankind, begins at science but ends at himself, the Napoleon complex of both intelligence and imagination. On the other hand the anti-theist wouldn't survive without a deity beyond himself to hunt. He doesn't pretend, he simply nullifies his own position.