Don't know much about Mythology? Barnes and Noble have you covered in this week's Free Fridays book selection, Don't Know Much About Mythology, by Kenneth C. Davis.
I know, well, not much on the subject, though my husband is more knowledgeable. It seems mythology plays a role in all things Super Hero! We recently watched Thor and it was pretty good.
I also recommend checking out one of the comments as the author of the comment lists a lot of other free books you might have missed.