Kemps

Google says, "Kemps or Scenics is a matching card game for two to six teams of two players each. It is played with a standard 52-card deck."

Each player gets a partner and sets up secret signals to tell the other when to say "Kemp". The goal of the game is to get 4 of the same card, and get their partner to say "Kemp". If someone has 4 of the same card and their partner says "Kemp", then that group gets a letter(starting with K, then E, and M, then finally P). whichever group spells "K-E-M-P" first wins.

There is a twist to this game, however; if a person suspects another person having 4 of the same cards, they can yell "Stop Kemp." (or Counter.) If the suspected person does in fact have 4 of a kind, that group loses a letter. If they don't have 4 of a kind, the group who yelled "stop Kemp" loses a letter.

See this page for more detailed rules