Are there "general interest" public data sets that I can download in csv or xml...

[canterbury10]

...format to use on my website? I have a database-driven site using PHP, and I'm wondering if there is some "general interest" data sets (ideally in csv format) that I can download to use with my site for various fun or informational purposes. I've found some public databases online, but they are all on extremely narrow topics such as the relative size of fish bladders in American rivers and half-life decay rates of radioisotopes. I thought maybe there were public databases containing the names of constellations or the capitals of countries or important dates in history. If such databases are not usually available for free, can I buy such databases somewhere for a reasonable price. Again, my goal in find such databases is so that I can then maniuplate them using PHP scripts of my own making to provide helpful little site-related lists and interactive features for my readers.

Thanks!