Via DF, Ziptastic is “a simple API that allows people to ask which Country, State and City are associated with a Zip Code.” This is truly excellent, and it addresses a longstanding pet peeve of mine.
In a similar vein, I’m pleased to announce my latest project. Ageist is a simple API to determine whether or not an individual is older than 13 given his or her birthday. (As an example, click here to see how old the Pixies album Trompe le Monde is, if you want to be really depressed.) While it does not (yet) calculate one’s racing age, I suspect certain race-registration websites could employ some combination of Ziptastic and Ageist to eliminate most of my user-experience complaints.