Math games/toys bleg

Dale is good at math. He started the kindergarten book when he was around 3, I think, because it was yellow. Scoop was his favorite character in his favorite show so it made sense to me.

Now he's 6 and has started the second grade book. He gets the concepts with ease--time, money, fractions, even multiplication from his sister--not a problem. I think he gets bored before he gets stumped. Therein lay the problem.

So I'm looking for puzzles, games, toys, etc. that will capitalize on this. We already have Cuisenaire rods and I have plans to get those out more often. I remember these puzzles from when I was younger. They were about the size of a Rubik's Cube and involved putting three-dimensional pieces back into the clear box. Different colors were different degrees of difficulty--yellow was the easiest; white and blue were harder. I think there were red and green, too.
I can't Google or eBay them because I don't remember what they were called. Anyone else know what I'm talking about?

I don't want to just add busywork; as a former school teacher, homeschooler, and parent I know "more work" doesn't mean much if it's "more of the same." That's punishment, not enrichment.

And let me add this caveat--I know there have to be tons of computer games, software, and websites for this, but I'm reluctant to start those. He has a hard enough time tearing himself away from the computer for things like meals and chores; I don't want to add to the list.

Thanks!