I have another interpretation which I think is cool. (By the way, the thing about God saying 'let there be light' is pretty damn clever.) My interpretation is that the Bible (the Book) calls itself God (or God's word, anyway), but the Bible is insane and deluded, and its truer identity is Satan. God is the Bible idealized, and Satan is the Bible projected (like the psychological defense mechanism of projection).

So, when the Bible goes off about Satan, you can get a lot of clues as to the true nature of the Bible itself: Satan (the Bible) is a great deceiver, is the cause of evil thoughts in the world, etc. Essentially, the Bible IS Satan, but Satan is such a great deceiver that it deceived itself, thinking that itself is God, rather than Satan. Basically, since the Bible is a fixed book, it is deceived, but cannot correct itself. So, it happily goes about professing it is God, or God's word, that it is all powerful (another deception; the book is only powerful in the minds of those who believe it), all knowing (it only knows what its believers know), all good (it's only as good as its believers), etc.

Try that interpretation on for a while, anthropomorphize the Bible as Satan, except that Satan deceives even himself, and you will see things in a different light. It's kind of amusing, IMO. It's very useful, as well, considering that the Bible DOES contain shitloads of deception, mind-control, and subterfuge.

Here's how I'd explain it to Christians: Satan is trying to turn people away from God, right? Something that is good at turning people from God is other religions, like Islam, Hinduism, etc., right? So, it makes sense that Satan would try to invent his own religion, right? Now, Satan is a deceiver, right? So it makes sense that if Satan decides to make a religion, it would be a deceptive religion, right, tricking people into believing false things, right? And the best way to do that is to deceive the followers of Satan with lies, all the while telling those followers that they are following God, right? In other words, Satan's unholy book would lie and say that it was written by God, God's word, like how the Quran claims that it is God's word, right? And just so nobody figured it out, Satan would be sure to include himself in the story as the bad guy, right? That would be the ultimate deception.

And Satan would tell you that thoughts of the outside world are evil thoughts, and thoughts of his book are the only good thoughts, right? He might even whisper lies to his followers, pretending to be the voice of God talking to the followers, right? And since Satan is the ultimate deceiver, he would be able to make the followers FEEL that they know the absolute truth, straight from God, right? Meanwhile he laughs as his plan works perfectly, turning those who most want to find God into blind followers of Satan, right?

Etc. etc. Essentially, you could lay out all of the mind-control techniques of the Bible, one after the other, and explain how they are all examples of Satan pulling one over on people. Now, here's the punchline:

And Satan is the ULTIMATE deceiver, right? So his false religion should be the most popular religion in the world, right? Even true followers of God would not be the most popular religion, because the path is narrow and few enter, right? So, what is the most popular book that preaches this deceptive message of God that is actually Satan in disguise? That's right. The Bible itself. 

Any objections can be dealt with by showing how Satan is such a good deceiver that he can even deceive you into defending the Bible. Even the minor truths that are in the Bible are part of the deception, since no book would be believed if it was all completely false.