As a general rule, these memes tend to point out an inconsistency with some facet of Christianity. They're nothing groundbreaking, but they do get their point across in a concise, funny and sometimes unconventional way. I'll start with a few choice sayings from the big man himself:
The Scumbag Christian meme focuses on apparent hypocrisies common among Christians themselves. It features particularly obtuse fundamentalist Kirk Cameron wearing the Scumbag Hat as its primary inspiration:
Philosoraptor may use some unusual reasoning to reach his conclusions, but he often does have a good point to make:
And here's Condescending Wonka to raise a few final issues in his lovably patronizing tone:
If you like these, there are hundreds more in the r/AdviceAtheists subreddit. Personally, though, I think of them as I would a particularly rich dessert: slightly nauseating when consumed too often, but delightful in moderation.