- The parameters of the universe (e.g. speed of light, gravitational constant, etc...) are extremely finely tuned for the support of living beings, and is unexplainable through science
- Our sense of morality (especially pure altruism) is unexplainable from the perspective of evolution
- Our universal longing for God is unexplainable from the perspective of evolution and rational thought
Each of the arguments has the same form: "I don't know how to currently explain something, therefore it is unexplainable in principle, therefore there must be a God." Taken to its extreme, we can find Colbert's summary "There must be a God, because I don't know how things work." particularly appropriate.
It's really a bold religious statement, ironically full of the arrogance that religious people often attribute to scientists. By saying that our current knowledge cannot explain something, therefore it can never be explained, is stating that you know better than all other future generations of people.
The problem with the statements, however, is not the arrogance. It is that they are show-stoppers: once you make the claim that something is unexplainable, then you stop looking. So-called Intelligence Design suffers from the same problem: by saying that a designer is needed to create the stated irreducibly complex mechanisms, then there is no use in searching for an explanation. It stops science, stops curiosity, stops investigation.
These types of arguments, then, are not just wrong they are dangerous because they stop the types of inquiry that could possibly show that they are wrong. In this way, they have a tendency to protect themselves in the world of memes.
I am not saying that we have answers to points 1-3 above (although I think we have some very good ideas at least for 2 and 3), but to go from ignorance to "God must have done it" is extremely sloppy logic, if it can be called logic at all.