We've all been there: you're out and about, doing your thing, when all of a sudden you realize that you've got to–you know, "go"–and you've got to go now! Unless you're out in the middle of the forest, that means you've got to find the closest publicly accessible restroom. Rest area? Gas station? Store with the sign "no public restrooms?" You've just found yourself in a bit of a pickle.
MizPee may be the solution for your pressing need. Using your smartphone, go to their website and enter your current city and state, and they'll give you a list of close-by facilities. Their list is pretty thin at this point, so they're eager to get your input on restrooms you know about. You can also give them feedback about facilities that they list.
They've also got a trivia section, so you can see how much you really know about "the necessarium."
MizPee is a free service.