I have been a DM for a long time. Recently I started school at a university. Naturally curious to find more friends with similar interests, I published a flier for D&D game night, open to anyone to apply and join. I got back a lot of people interested in joining, and I scheduled a game night for Saturday. Come Saturday morning, I had cleaned my house (I live off campus) and got it nice and spiffy for my guests. Feeling like I wanted to make a good impression, I prepared some coleslaw, sweet lemon tea, chicken nuggets, ladyfingers, tater tots and barbeque pork sliders.
The players arrived, and we began with a simple dungeon romp to recover an artifact stolen from a traveling scholar. The players entered, and had a pretty good time fighting, exploring and dungeon delving in general. After defeating the boss of the dungeon, a rather nasty and powerful troll, the players began to go over the treasure they had collected. Among them was a ring that increased the wearer's strength. The party rogue put it on because she needed it to help give her a better strength score, but naturally the barbarian demanded it claiming it was meant for him.
Suddenly, out of character arguing began at the table. They were meta-gaming and bickering about who should get the loot, and the argument began to get quite heated. The player playing the rogue asked the player playing the cleric if she should get the ring, and he agreed. This upset the player playing the barbarian, let's just call him Carlos, who immediately responded by claiming that she was a "loot whore" and he'd butcher both of their characters if she didn't give him it. The cleric stood up suddenly from the table and began pointing and shouting, and the barbarian grabbed a pork slider and smashed it into the cleric's head. An all out food fight began as people began grabbing their food and throwing it at each other, and before I knew it the table was overturned, the night was ruined and I was standing in a room of messy, overly excited people laughing and carrying on as if this was perfectly normal. They began to leave and I was asked, "When is the next game?" I responded, "I don't know." and they thanked me for the night and left.
I can't have another night like this. How do I tell them that I'm done?