People get together and drink socially and then start throwing things. Let's hope that in most circumstances, it's in a socially acceptable drinking game like beer pong, or in a pub sport like darts. In ancient Greece, among the wealthy classes, those games would involve throwing wine itself! That's fine, as long as you aren't in danger of running out of wine. It wouldn't go over too well in modern establishments where carpet cleaning can be a hassle. The game was called kottabos, and it involved flinging the dregs of wine from your own cup at objects to hit a target.
Critias, the 5th century academic and writer, wrote about this “glorious invention” stemming from Sicily, “where we put up a target to shoot at with drops from our wine-cup whenever we drink it.” While a handful of modern academics question the game’s Sicilian origins, kottabos definitely spread throughout parts of Italy (as the Etruscans played it) and Greece, too. The kottabos craze even resulted in industrious people building special round rooms where it could be played, so all competitors could be equidistant from the target.
If you were good at kottabos, you could be a winner. If you were bad at it, you'd still provide entertainment to other partiers. There was both a musical and a quiet version of the game, and precise techniques for the act of flinging. Read all about kottabos at Atlas Obscura. Some images may possibly be NSFW.