At webkendoku.com you can play this highly addicting logic and math puzzle game KenKen in both online and printable formats for free.
It is loosely based on killer sudoku and goes by a number of names including KenKen™, kendoku, kenduko, cancan, square wisdom, minuplu, calcudoku, and/or latincalc. It is also similar to a crossword or jigsaw puzzle since it requires trial and error to solve.
Jan 20 09 - based on a couple requests, we created a "no-op" (no operations) version of the game, if you wanna give it a try, visit http://www.webkendoku.com/no-op
Jan 9 09 - created a load game, you can find it at http://www.webkendoku.com/load
Jan 4 09 - to match the yesterday we added more 6x6 games today too, there are now over 250 games available to play, enjoy
Jan 3 09 - just added more 4x4 games today, there are now over 250 games available to play, enjoy
for more updates, visit our blog