Study skills can also be taught, in a way, through an extracurricular activity. I have found music lessons to be great for providing a challenge to my son, anyway.

Music helps instill a work ethic and self-discipline, and also provides an outlet for self-expression and creativity, working both "sides" of the brain, if you will. It is also one of those activities which require work, even if you have talent, so my son has learned he can't skate by in everything. smile