I rarely say things like that, so it's worth explaining that I say it because I have just been put on a most literally in-house assignment -- write something that, given some standard recipes, will spit out a reasonable approximation of a grocery list.
Now, to do this 100% properly would require an inventory of everything in the house. That's just not going to happen any time soon. (I think I will keep track of what things we have bulk amounts of, such as flour and sugar, because those items tend to be on hand no matter what.)
Anyway, I'll probably get crankin' on that in the next few hours here.
I've discussed the features needed with the client (sts) and there will be a command-line interface and then a Tk interface, and that's it. Apparently a CGI would be useless. (IMHO, it would be useful because then recipes could be input from anywhere...but I digress.)