Coup, by Rikki Tahta, is a tiny card game about bluffing your way to power. Each player has two face-down character cards (their influence) and a couple of coins, and can claim to be any character, whether they hold it or not.
Lose both cards and you're out. Last player standing wins. It's quick, cheap and a favourite warm-up at game nights.

A 15-minute bluffing game where anyone might be lying.
Take three coins as tax. Blocks Foreign Aid.
Pay three coins to make a player lose a card.
Steal two coins from another player. Blocks stealing.
Swap cards with the court deck. Blocks stealing.
Blocks assassination.
Each player gets two face-down character cards and two coins.
On your turn take one action: Income (one coin), Foreign Aid (two coins, can be blocked by a Duke), a Coup (pay seven coins to make someone lose a card; you must do this at ten coins), or a character action.
You can claim any character's action or block, whether you hold that card or not.
Anyone can challenge a claim. If you were lying, you lose a card; if you were telling the truth, the challenger loses one and you swap your revealed card for a new one.
A player with no face-down cards left is out.
Bluff early, when nobody has a read on you yet.
Watch who claims what, and challenge when two people claim the same character too often.
Upcoming SyncTrip board-game and social deduction nights. Most people come alone.
Two to six, and it's best with four to six.
About fifteen minutes, so groups usually play several rounds.