I've had trouble with all of the things you mentioned. I seem to be more "autistic" when I'm in a crappy mood LOL. Sarcasm I've been pretty good with understanding, and the extreme interest thing... has occurred in the past. For example, I'll be "obsessed" with a specific band such as Metallica or Dream Theater, but not, let's say, metal or rock in general. Even with computers, I'll be fascinated with a certain aspect of them for a certain period of time (eg: comparison of certain types of software such as web browsers--On a related note, Google Chrome FTW! )
And also, I realize that this is just a stereotype, but I don't have that math thing... Sure, I'm pretty good with math, I can do basic operations like adding, subtracting, multiplying, etc... in my head fairly easily, but I need scrap paper or a calculator to do some really long algebraic equation. So, I'm no Rain Man lol.