For a recent project, I had need of simple Python libraries for currency conversion, stock quotes, and airport code lookup. In the past, I was using perl for this, so I used Finance::Currency::Convert::XE and Finance::Quote.
But since I'm using Python here, those aren't available to me. And unfortunately, I couldn't find anything on the web either.
And for the airport codes, I got a list and stuck it in a database. But then I have to maintain that... and that's annoying.