A friend told me about Duolingo - a free learn-a-language site. You can choose how active you want to be, set goals, and it is arranged almost like a game. I took five years of Spanish in school, but barely remember, "Como esta usted?" (How are you?). It's something I can work on whenever I need to take a break, and provides good brain exercise.
Would also work as a great crave buster - and you would actually be learning something while you aren't smoking!
How cool is THAT?