So, I finally clicked on that KENKEN link on NYT's crossword puzzle site and found a great new puzzle. Here's Will Shortz to tell us all about it:
And here's the page to get daily doses at whatever challenge level you crave: http://www.nytimes.com/ref/crosswords/kenken.html. Seems quite addictive … sudoku with a bit more depth. Try it out and tell me what you think. Seems like a great combination of arithmetic and logic for kids — I'm going to see if my 7-yr-old likes it too. UPDATE [a few minutes later]: OK, this is structurally only superficially like the sudoku, but it is indeed quite addictive!