I'm reading this book by self-confessed punctuation geek, Lynne Truss. It's really quite funny - fascinating too. I wouldn't have thought that a book about the right and wrong ways to use commas, colons etc would be so readable. I've learned a bit too - now I know when to use semi-colons and when to put an apostrophe in 'its'.
No, really - it's a bloody good book. And I'm not just saying that because I'm the sort of person who finds stationery attractive (only some kinds, and only platonically).