The problem for us in doing the CTY math is that it feels like a "bridge to nowhere." I'm not sure I want my son to do third grade math in 3 months, then 4th grade, then 5th grade... It looks boring too to do all of that repetition. We are doing a little bit out of a few math workbooks daily, which works for us. The CTY courses are also very expensive- like $800 for one course for 3 months.
He can take courses for gifted children at our local community college in the summer, but not until next year. Grrr!! I'm scrambling to find things again for this summer.