This simple and navigable site contains hundreds of thousands of searchable recipes submitted by home cooks (totally doable, even for the kitchen-challenged). You can even search for recipes using specific ingredients if you have random leftover ingredients that you would like to use up.
Very cool is the option of scaling the original recipe yield for the number of servings. They even have a nutritional breakdown for each recipe, a section on similar recipes, downloadable cookbooks (their summer picnic cookbook is pretty good), and an entire section on budget-friendly recipes. I’m a fan of their shopping list feature, where you can save recipes in your recipe box and the site creates a shopping list organized by category (e.g. produce, meat, dairy, etc.). How convenient.
The best part about this site is that the recipes are reviewed and rated by users, and a sizable proportion of them have creative modification suggestions (to make the end result tastier, healthier, or even better, both!).
I didn't even like lemon bars until I tried these (check out the modification suggested by the second reviewer - it's best with freshly squeezed lemon juice):
http://allrecipes.com/Recipe/Bake-Sale-Lemon-Bars/Detail.aspx