Viewable at: (http://www.macromeal.com)
This is a sample ruby on rails app that works like allrecipes.com, but for people who have a macronutrient restriction in their diet.
Recipes require macronutrient information to be added, and then can be searched for using a range of macronutrients required, along with name.
It's pretty small and features user accounts, simple search (by name), advanced search (by name and macronutrient ranges specified), and authorization (small authr I built by myself to restrict editing/deleting of recipes only to the user who created it).