Strange & Surprising Facts About Ancient Greece

This is Aphrodisia: Women, Sex, and Pleasure in the Classical World. The title's probably self-explanatory, but it's an examination of the sex lives of women in both ancient Greece and ancient Rome.

Battling the Gods: Atheism in the Ancient World by Tim Whitmarsh, which is an absolutely phenomenal book that looks at, like I said, the spectrum of atheism in antiquity.

And if you'd like to learn more about ancient Sparta in general, an excellent introduction to the topic is The Spartans: An Epic History by Dr. Paul Cartledge.

The Law in Classical Athens by Douglas M. MacDowell, an excellent read that you will probably find many more surprises within.