I highly recommend Art of Problem Solving online courses to anyone with a mathy kid who is frustrated with school offerings. DS11 has finally found a math course that requires him to think and moves at his pace. All of the other students in the class seem to be at the same general level also, so there's not a lot of time wasted on explaining concepts over and over again. Their intro courses start with Algebra, Geometry, Number Theory, and Probability and go up from there. Well worth the price (about $350 for the 6 month courses)IMO!

Disclaimer: I would only enroll a very high math ability kid in these courses. Also, they require computer skills (fast typing) and ability to read quickly to get the most out of them. There's weekly homework and Challenge sets every 6 weeks, so some independent time management and organization skills are necessary, or else a lot of support from parents.