"Frank's Zoo" is a simple card game designed by Doris & Frank. It can be played by 3 to 7 players, but is best with 4 to 6. The game consists of 60 cards, that depict animals. The cards are divided amongst the players, and the goal of the game is to get rid of one's cards as quickly as possible. Each animal is the prey of several other animals, which are its predators. To play a card, it must be a predator for the last animal played (and only animals of one type can be played, and the number of cards payed must be the same as the last move) or it must be the same animal as the last one played, but one more (e.g., two lions are defeated by two elephants or three lions). The game also contains one joker. The mosquito is a special card: it can be played by itself as a rather weak animal, but it can also be added to one or more elephants, and then it will turn into an elephant. For more details on the rules, see Boardgamegeek.
For the ROLEC project, a Frank's Zoo engine was developed by Loes Braun. This engine can be used to let several Frank's Zoo AIs play against each other. I have used this in courses, and will continue to do so. The engine is available here.