http://forums.welltrainedmind.com/forumdisplay.php?f=5That board is a homeschoolers board for parents to exchange ideas on how to give their kids a rigorous education. That link is a subforum for highschool students or adults who are self educating. I recommend looking at it because it seems those people value education for its own sake and not just as a means to an end.
Beyond that have you considered academic competitions? Math Olympiads? Spelling Bees? Have you heard of "the art of problem solving"? I believe it's free. I know the alchemus part and the math jams are.
http://www.artofproblemsolving.com/School/index.phpKhan academy is another free online resource for self-educating.
http://www.khanacademy.org/Kudos on seeking out a way to be challenged on your own time.
