I know some sign language. Know the alphabet, numbers and some basic gestures.
I also learned a lot from my 2 year old niece, believe it or not. Her mom has DVD's called "Signing Times". They teach kids sign language. Now when she speaks she often signs at the same time. Sometimes she will just sign, like when she has had enough to eat.
I would like to take a class someday so I can become fluent.