Last week I released a puzzle on squobble.com, conveniently dubbed the "Squobble Puzzle". It's quite similar to Sudoku, so the hardcore Sudoku players might find this brain-teaser an entertaining alternative.
Basic Sudoku is played with 9 symbols, which are generally the numbers 1 till 9. Other than numbers, these can be anything from 9 letters to 9 colours (for the rules, check out Wikipedia). I combined a "number Sudoku" with a "colour Sudoku" to obtain the Squobble Puzzle. This has some interesting consequences. For instance, only certain combinations of numbers and colours are possible. Also, the classic Sudoku tricks can be applied on numbers, colours or both, and even new solution methods can be found.
I included a beginner and expert level (if you're good they should take you about 5 and 15 minutes respectively), and the standard options: reset, choosing a puzzle by number or randomly. Moreover, every puzzle has a unique solution. Finally, to guarantee your satisfaction, dear reader, all of this was molded neatly into a Flash puzzle with drag-and-drop support.
Anyway, the list of features-to-add includes a charts system for best times and other records, a classic Sudoku page, etc. Whether I implement these will depend mostly on visitor feedback and the local weather forecast (a lot of rain means more features).