One of my major geeky interests is religious history, particularly in the form of a) fairy stories/fairy lore and taxonomy (i.e. Irish folk history, Jungian and other analysis of the content of fairy stories, et. al.), b) ancient Mesopotamian history (anything and everything I can get, but the Sumerian and Babylonian polytheistic traditions are fascinating), and c) early Christianity (which is to say Judaism and early Christian or Christian-like sects in Palestine and the surrounding area in the first century CE). (Islamic religious history I place in another category, which is to say that it's a branching of my actual area of focus and therefore not simply an area of geekdom).
All of this is by way of saying that while some people may spend their Saturday nights out drinking and partying, I spent mine drinking and watching Blade Runner with my roommate (a deep meditation on existence and mortality if ever I saw one) and then watched a lengthy lecture on the location of the historical Jesus within Jewish sectarian and mainstream tradition. I share it because, as I said, I'm having a nerd moment.
Enjoy, if this is your thing!