: Your route planning idea is fine, except where are you going to get the raw data from? Regular mapping programs use people who drive around with a GPS, but there simply isn't the budget for enough of these to provide any sort of real-time (or even recent) monitoring of road conditions. You'd have to have devices built into the cars to track average speed along each stretch of road during each time segment. I'm sure some company somewhere is working on this already.
Your recipe idea could work, assuming you had enough people to collect recipes and enter them according to your rather detailed specs. There's no reason why you shouldn't be able to enter a type of food, a cooking method, a time limit, and a list of main ingredients and get a list of optimal recipes. The allergies and food intolerances would be easy to add later, since those are based on ingredients and food types and probably won't need any additional data entry.
The memorable passwords generator has to do with how the mind works more than anything else. This sounds like the most interesting puzzle to solve.