I've never dreamt code before, but I have spontaneously thought in code. A couple of times, structs and macros (even a function once, that I now forget) just popped in my head (it always looked more like pseudocode than C though) while trying to figure completely unrelated things out. It's kinda' cool, I think, it's never happened enough to annoy me.
The one I get the biggest kick of, is, once a Trinitarian was trying to explain to me how the Trinity works, when boom, I get
Code:
struct God
{
Father;
Son;
Holy Ghost;
};
:p