I (and co-hackers) are building a sort of trivia game inspired by this blog post: http://messymatters.com/calibration. The idea is to give confidence intervals and learn how to be calibrated (when you're "90% sure" you should be right 90% of the time).
We're thus looking for, ideally, thousands of questions with unambiguous numerical answers. Also, they shouldn't be too boring. There are a lot of random statistics out there -- eg, enclosed water area in different countries -- that would make the game mind-numbing. Things like release dates of classic movies are more interesting (to most people).
Other interesting ones we've found include Olympic records, median incomes for different professions, dates of famous inventions, and celebrity ages. Scraping things like above, by the way, was my reason for asking this question: http://stackoverflow.com/questions/2611418/scrape-html-tables
So, if you know of other sources of interesting numerical facts (in a parsable form) I'm eager for pointers to them. Thanks!