I'm sure by now most of you have heard of the Atheist Debater iPhone app, or other similar apps that are an invaluable tool to many atheists who may find themselves in a debate, or want to plan ahead with some speaking points.

Ask why. Don't get defensive... Just ask them why they believe this. You want the specific details before you proceed. Ask for them and then sit back and wait. You'll find that 95% of people who make this claim have no clue about specifics. They are just repeating what they've heard. If they can't cite specific errors, you can point out that they've no evidence for their claim. If they are able to name specifics, write them down carefully, go research them, and get back to them with a solid answer.

That is literally it. I mean, tell me the above answer didn't make you chuckle at least a little. That answer provides no help to Christians who are confronted with this question. Just send them over to http://thethinkingatheist.com/bible_contradictions.html and watch their heads explode. That lists many, if not all, of the contradictions present in the Bible.

Ask "Why do you believe this?" ... They may cite the Crusades, or the Witch Hunts. Agree that these were evil events, but...that they were not consistent with Christian teaching. Not everything done in the name of Christianity reflects true Christianity. Additionally, point out that...they pale in comparison to the scope of evil enacted by the atheistic regimes that killed almost 100 million people in the 20th century alone.

Oh, not the old "atheist regime" argument again. First off, the Crusades and Witch Hunts were, in fact, consistent with many Christian teachings of their times. They were claimed to have been done in the name of Christianity because they were done in the name of Christianity. The groups behind each of the travesties listed above truly believed they represented the best interests of their religious group.

Many people mistakenly think science is the only source of knowledge. If science can't prove a belief, it must be false. Expose this faulty thinking with a simple question: What scientific experiment proved that this is true? If they only believe what science has proven, then that belief itself must be proven. But this belief doesn't come from science. It is an assumption that cannot be proven. Thus the person who says all beliefs must be proven by science is guilty of a self-refuting belief.

I am absolutely stunned. That's it? Use circular logic to somehow disprove all of science? There's a reason why this argument never works. We know that the scientific method works in proving hypotheses because it can be demonstrated to be true. If a scientist posits that plants are green because of chlorophyl, then it can be demonstrated to be true by using the scientific method, experimentation, and testing.