Etymology is the study of the history and evolution of words, phrases, and slangs. It’s an ology that’s actually fun, in this nerd’s opinion.
For instance, aren’t you curious about the origins of the words gargantuan, cyberspace, yahoo, chortle, nerd, and bump? Take a look here to find out.
And here’s one of my favorite Shakespearean references: look at all these phrases attributed to the Bard! (At least by this source; I’m not sure of its credibility, but isn’t it fun?)