Boo Who?

From BoardGameGeek:

An easy card game for up to 4 players that utilizes memory and strategy. Over 5 rounds, players attempt to swap out their cards to achieve the lowest value amongst their hand before calling out 'Boo' to end the round. Each round has a different condition on how many cards you may peek at prior to the start or double value for round 5. Lowest score wins the game. There are action cards that allow you to look at your cards, other player cards, and more.