Are you looking for after-school enrichment, acceleration suggestions that would work within the school, or a homeschooling curriculum?

Are you in the US? What's your state? If it is on the Common Core Standard: http://www.cde.ca.gov/ci/cc/

For math, Khan Academy is free and will give you a nice progression of skills: http://www.khanacademy.org/exercisedashboard

If you are looking for a complete curriculum, Singapore Math is popular.

Browse around, there are literally hundreds of suggestions in the forums.