I studied French in high school and college, but never really learned to speak it fluently. It comes back, though, when I try to study Spanish. Funny how our minds work.
One year in high school I took a psychology class, and was selected to be one of the participants when a hypnotist came to do an assembly. I remember being on stage, pretty aware of everything, and--at least as far as I know--the hypnotist didn't single me out for anything. I'm not sure I was actually hypnotized.
But I was definitely very, very relaxed.
Right after the assembly, I had French class and was scheduled for an oral exam. Because I was so relaxed, the French just rolled right up into my consciousness and off of my tongue.
Incroyable, mais vrais!