First, they go to the laughable pooling of ignorance sites of atheism (such as the inane [ir]RationalWiki) and evolutionism (such as the absurd talk.origins) to find horrible "proofs" for their worldviews, and try to catch Christians and creationists with such nonsense. (It is very tedious to try to have anything resembling a discussion when someone posts nonsense from one of those sites as if it was a complete refutation of someone's position, but they do not engage in actual discourse.) It's amazing how people with little to no knowledge of theology, psychology, history, philosophy, ancient literature, culture, social customs, language, science and other things seem to think that they are going to be the ones to destroy God and Christianity. Sorry, Skippy, it's been tried by grown-ups much more intelligent than you for centuries, and we're still standing strong.
A variation is when they will ask a question that a Christian or a creationist cannot answer, and then use logical fallacies to "prove" that there is no God. I remember hearing a caller on Matt Slick's radio show (CARM.org) drop something on Matt at the very end of the show when the closing music was playing. Matt had not heard of the subject (nor had I, but big deal) and asked the caller to e-mail him information so he could research it. The atheist cackled with glee, and then bragged on his Weblog that he has stumped Matt. In all cases, Christians and creationists cannot know everything about everything. What a ridiculous standard to impose. It is hypocritical as well, since they would not make such unreasonable demands of other atheists, often bleating, "It's OK to admit that you don't know something". True — but be consistent.
Second, they play "Gotcha!" with personal attacks. This is even more outlandish than the first, and often occurs when the attacker has been shown that atheism is fundamentally flawed, or how sciences does not support evolution. The game is simple: Complain about character. It does not require accurate knowledge about Biblical teachings. If a Christian corrects the atheist, the player will just accuse him of being a hypocrite and making baby Jesus cry. The "logic" seems to run like this: "You are not a good enough Christian to please me. Christianity is false. There is no God!"
Of course, they exhibit appalling lack of knowledge of what the Bible really teaches, and requires occasional quote mining of Bible verses. When bitter, illogical apostates try these things, it's a toss-up whether they're being pitiful or being amusing . Some even claim to have been evangelical Christians at one time. Well... Raising your hand during an emotional moment to "accept Jesus" does not count, sorry to say. Nor does just attending a church or being a member of some religious organization.
The "Gotcha!" game is often played when atheopaths are bested in logic and are shown how atheism (and its ugly cousin, Deism) are incoherent, irrational worldviews. Since their worldviews do not have the necessary preconditions of human experience and are inconsistent, they borrow from the biblical creationist worldview. They hate this fact.