Skyrim's taverns. They're cozy, they're comfy, but to be perfectly honest, there's not a whole lot to do in them except run in and sell a load of collected crap to the innkeeper and maybe knock a few things off the tables as you rush back out.
The Tavern Games mod aims to change that by adding two dice games, a card game, a board game, and even lottery tickets to Skyrim's inns and pubs. Just walk up to anyone in the tavern and begin a conversation, and there will be a dialogue option to play a game. Provided they have enough money, they'll agree to play. I mean, what else do they have to do besides sitting silently while eating comically large loaves of bread?
The games are relatively simple, and there's no animation when you roll the dice or play the cards—they just appear on the table—but it's still a nice way to spend a few minutes and try to win some cash. Here are the table games:
One player rolls two dice, and then guesses if his opponents roll will be higher, lower, or equal. If you bet on equal and win, you receive triple the payout. Get it wrong, and you lose triple your bet.
One player rolls two dice, and the total of that roll is multiplied by three—let's call that new total the Jack. After a coin flip to determine who goes first, the two players roll dice, trying to get as close as they can to the Jack without going over. If you bust, the other player wins. Hit the Jack exactly, and you win twice the bet.
The Battle of Heroes
A card game. Each player draws and plays three cards with numbers on them between 1 and 10. Add them up and that's your Hero Power for the round. At that point, you can choose to roll the dice up to two times to add to your Hero Power, though that dice roll costs gold which goes directly to the other player. In other words, you have to balance how much you stand to lose by rolling against how much you stand to win by having a higher Hero Power than the other player. Granted, it ain't exactly Gwent, but at least you can attempt to cheat.
Talk to the innkeeper and you'll be able to buy a rulebook for these games for a couple Septims. You'll also be able ask the tavern owner to play a board game with you.
The Daedra Challenge
This is probably the simplest game: dice rolls happen automatically and your pieces move around the board by themselves, attempting to get to the center first. Land on an arrow and you slide to the spot the arrow is pointing. Land on a skull, and you're asked a multiple choice question. Get it wrong, and you go back to the start. If you win, you get a gift from the innkeeper.
If you're looking for straight-up no-skill gambling, you might try purchasing a lottery ticket. Open it in your inventory to see if you've won, and if so, redeem it with an innkeeper. Prizes can be any number of things: gold, a spell book, potions, ingots, and even several nights of free room and board. I won two ingots! It was my lucky day.
Of course, if you know one thing about the rabble haunting Skyrim's taverns, it's that they don't exactly have a ton of gold, so most of the games you play will be of the low stakes variety (unless you yourself are just starting out and don't have much cash of your own). I did find a gambler named Gambler in the tavern in Solitude, however, who had a decent amount of Septims. He no longer does, thanks to a couple games of Dice Jack.