Does your code pass the Turkey test?
I saw this one on Dot Net Kicks today. I have seen all of this in different places before, but this blog nicely summarizes all the differences and shows great examples to boot.
The basic jist is whether your dot net code could run in Turkey. Their date format is different, they have arabic numbers (not just 0-9), and they use . for currency separators (not the , we do in the US).
Great article.