Here's an Amazon search with lots of possibilities for enrichment:
A user here, Tallulah, recommended the "Math for the Gifted Student" workbook series put out by Flash Kids, and we also liked it quite a lot. It is anti-repetitive, if anything. The Flash Skills Problem Solving mini-workbooks are also nice in my opinion, and much less repetitive than something like Kumon; here's a sample:
http://www.amazon.com/Problem-Solvi...UTF8&qid=1302201868&sr=8-3-spell(Note: I may seem like an Amazon shill, but that's just because I get free shipping from them and tend to start my searches and book-shopping there, have favorites/bookmarks there, and like to see user reviews at a glance. Shop around for the best deal, of course.)
We've used IXL math (ixl.com) and it is pretty good for keeping things from getting boring, because the student can jump around. However, it doesn't offer lessons at all.
The thing is, neither Kumon nor these other sorts of enrichment options do much for teaching math concepts. I think you should look at Singapore Math etc. for that; you need a real curriculum.
