Mother Tongue by Bill Bryson
Bryson is my new favorite author. He somehow manages to dig up all sorts of quirky facts I'd never heard about subjects I thought I knew about. I just finished reading his Mother Tongue on the history and study of English. It was nearly as good as his Short History of Nearly Everything (though this is on science, a subject closer to my heart). I also love how he skewers past pedants and their outdated ideas. Even when they're easy targets, with his light touch it's still fun to read.