Perl, Lisp, Ruby ét all. Always wanted to learn at least one.
Website design - I can knock together basic HTML, CSS and Java, but that's all. I have absolutely no design sense.
Photoshop - People keep asking me to do things for them in Photoshop as they know I am experienced with computers, but I haven't a clue!
Still getting my head around multi-threaded code, especially in C++. It can really make things x10 harder to write.
Supreme Commander. I'm truly abysmal, and what ever I do, I never seem to improve.