LostSoul
Adventurer
I was trying to figure out how to fit in clerics and paladins in a post-apocalyptic/sci-fi game set on Earth. I'm not quite willing to go down the route of "you were worshiping an ancient AI/alien all along! Hah! Hah! Hah!"...but after playing Paizo's Iron Gods I really like the idea of AIs having the ability to grant spells to their worshipers...
In my game Clerics gain their power from their devout worldview, along with a few Words of Power. I have training times for gaining levels, and clerics need to get high on drugs in order to twist their minds to see their worldview more closely. They think that the gods give them power, but it's just because the gods chose to make people think this way (thus religion). All they need is the Word and the Will.
I always planned on having that be one of the game secrets but I think all the players know it (I allow "metagaming" in order to achieve maximum immersion), but eh.