Coup is an inexpensive short bluffing game that plays best in groups of 4 or 5 players: less players and the game is not that great; more players and the downtime is pretty high. If you also consider that this game has player elimination, you don't want the players that are out of the round to be sitting without being able to play for too long.
In this card game each player is dealt two cards. Each card represents a person that the player can influence to perform actions: steal money from another player, assassinate, block assassinations, etc. The fun part of the game is that you don't need the appropriate character to be able to perform those actions, you can just bluff and pretend that you have a particular character. If nobody calls your bluff, then you're fine. If they call your bluff and you were lying, you lose one of your cards.
The game ends when there's only one person that hasn't been eliminated. Unfortunately when there are three players left, this game has a bit of a kingmaking situation, where one person knows they can't win, but gets to decide which of the other two players will. That lowers the rating of this game a bit for me.