A strong desire to never get laid?...Ok, I kid. I don’t know about today, but, when I played we had several of the books like the Dungeon Master’s guide, Players Handbook, Monster Manual (and a few others), along with at least a few rudimentary adventures (that you can buy at the same stores that sell the books, or of course, online). You need dice, some figurines, and a few willing friends to play with. Take all this with a grain of salt however. Maybe things are different today, with computer simulations and all that.