SuperCook - enter a few ingredients, it will tell you what recipes you can make
supercook.com
supercook.com
EDIT: After playing with this for a few minutes I decided I don't like how entering ingredients works. Why can't I enter more than one at a time? If I enter "garbanzo lemon", supercook thinks there's some kind of ingredient called "garbanzo lemon".
Also, what would make this really shine is if supercook had the ability to differentiate between a main ingredient and an accent ingredient. If I say all I have is bacon, supercook shouldn't suggest that I make bacon-wrapped scallops...
EDIT again: (I'm getting carried away): supercook should differentiate between main ingredients, accent ingredients and things that most people have. So, if I say that I all I have is bacon, supercook should suggest carbonara as a strong possiblity. Most people have some form of spaghetti/linguini and milk or cream. Anyone up for launching a competitor?
I can see this idea applied to drink recipes, though. I often have 3 or 4 half-empty bottles of different types of liquor- it would be great to get a list of 10 different drinks I could make with friends. On second thought, $10 says there's already a Facebook App that does exactly that...
Also, this something that search engines could do for 10 years. I worked in a Internet cafe and I explained to a old woman that a search engine allowed you to search by content. She reponded "Does that mean if I search for a list of ingredients, I get a recipe?"
This was an absolutely geniusly insightful response. Indeed, I distinctly remember trying this technique with AltaVista at least 10 years ago. Of course, then, the number of webpages was sparse compared to nowadays. So, AltaVista allowed partial matches. Nowadays, you'd only get an exact match.
Pretty cool app.
> Tortillas, yogurt
You can make:
> Dog Food
You will also need:
> Dog Food
...? Excellent.