You've Got Crabs
How it works: Pick a partner and establish a secret signal, like touching your nose or blinking a lot. Collect crab cards and try to get a matching set. If you get a matching set, you have crabs. Try to communicate this to your partner using your secret signal. If your partner yells "YOU'VE GOT CRABS" you get a point. If an opponent figures it out first and yells "YOU'VE GOT CRABS" you lose a point. Whoever catches the most crabs wins.
Players: 4-10 (Team based requires an even number of players)
Time: 20 mins