If you are interested in metaphysics and the meaning of existence (and want to impress your friends), ontology may be a good field of study for you.
Ontology comes from two Greek words: on, which means "being," and logia, which means "study." So ontology is the study of being alive and existing. Heady stuff, but something we all ponder at one point or another. When you see the word ontology, think of Hamlet agonizing over "To be, or not to be" or Descartes stating "I think, therefore I am."