Let me introduce you to a great friend of mine, The Nameless Game. It's not so much that the game has no name, it's that it went so long without a name that it was simply known as The Nameless Game, which then went on to become its name.
This game arose from our frequent Magic sessions where one player would invariably have to go make a phone call, go talk to his wife, reshuffle their deck, answer the door for pizza, etcetebla and leave the game hanging on pause. What did the other players do? They developed The Nameless Game. Now I'm sure that one person suggested it and then another player agreed to try it but I don't recall who it was who had the stroke of genius to come up with it in the first place (though I know it was not me). The game went on to become legendary. There is a d20 version, there's a version with character classes, there's a variant with a death stroke rule but nothing beats the original for pure, simple fun that anyone can enjoy in under five minutes.
The equipment: One six-sided die (d6)
1 - Each player rolls a d6 to determine their initiative (aka: who goes first). Highest roll wins and then proceed clockwise from there. Re-roll among the winners if there's a tie. Repeat until someone wins.
2 - If there are more than 2 players in the game, the starting player declares who is being attacked.
3 - The player rolls a d6.
= On a 5 or a 6, it's a hit.
= Anything else is a miss and the turn ends passing to next player (see step 5).
4 - If a hit is rolled, the player rolls the d6 again and does that much damage to the player they were attacking. (aka: the hit player reduces their life total by that many points)
= If the hit player is dead (aka: has no more points of life), they are eliminated and no longer roll to attack. I'll get to how much life you start with later.
5 - The turn ends and the next player starts their turn by declaring who they are attacking (see step 3).
6 - Repeat until only one remains.
That's the whole game.
Each player can have their own d6 or you can pass around a single d6. You can use pen and paper or counters to track totals but you really don't need to because you will rarely need to remember a number greater than 10. The length of the game is mostly determined by the initial life totals of each player. I find a good formula for a snappy game is: 20 / number of players (round up). So a 2-player clash has 10 points for each player to start with and 3 people = 7 points, 4 people = 5 points, and so on... Some people can be eliminated in the first round if the starting life is <=6 so you can always keep 7 as a minimum number if you really want but that kind of defeats the purpose of the game which is simply a hectic way to keep people with ADD amused for the 5 minutes of downtime that can occur during a gaming session.
It's amazing how intensely wrapped up in such a simple game we tend to get but shouting, cursing, boasting and taunting comes so easily in a game such as this. There's a lot of drama with each roll, and, as with all good games, it gets more dramatic the closer to the end you are. I suggest you try it if you're ever stuck for a quick game and all you have at hand is a teensy-weensy six-sided die.