I don't think I can ever say enough good things about Connie Willis. She achieves hilarious, easily readable science fiction with social commentary that is high-handed or over bearing. This book is about Oxford university in an alternate timeline where time travel is possible. History PhD students travel back to research and live in the times they study. There's very real, genuinely likable characters here, telling two parallel stories, one in the middle ages and one in the near future where viral plagues have decimated the population and are still popping up. A good introduction to Willis if you haven't read her before, though To Say Nothing of the Dog which takes place in the same universe is also excellent.
Damn, it's already August. Am I going to manage 21 more books before the end of the year? ACK! Maybe I should change my own rules and start including comic books, then I'll surely make it.