I found this blog somehow through a blogroll grapevine, which very cleverly combines Chinese and Math Puzzles: Pinyin Sudoku. The author posts Sudoku puzzles made up of similar sounding characters. So not only do you get to learn the differences in homophones, but you also bust your brain doing Sudoku puzzles. Check out this out this LUN one for example:
In this case it not only provides homophones, but you have to make sure you know your differences in radicals to not mix them up. Other examples vary a bit more in characters.
I find this implementation of Chinese learning extremely clever. It's the kind of association thinking that we need in creating new and unique ways to learn languages. What can we do make things interesting? What do you enjoy doing? How can you mix that with Chinese?
Unfortunately, I've always find Sudoku too frustrating. No, I don't suck at maths or puzzles :P. However, I'm sure there's others out there that enjoy Sudoku and want to mix it up with their Chinese learning.