To get your classroom involved in Ken Ken puzzles click here: KenKen Puzzles
In my math classroom, I have a Math Challenge Box, where students who finish early or who want to work on a challenge can visit.
One of the activities in the Math Challenge Box is KenKen puzzles.
I keep print outs of the weekly KenKen puzzles that arrive in my email box.
KenKen is like Sudoku, but involves math skills to arrive at the correct number to fill in the box.