Finished developing captainbrew.com a while ago, if you are interested you can try it here http://www.captainbrew.com/. You can create recipes, adjust gravity or bitterness, scale a recipe, create brew sessions and many more.
There are also other calculators included like Yeast Pitching Rate, Priming Sugar, Keg Carbonation, ABV , Sparge Water, Washed Yeast.