On your turn, start by rolling six dice. Pick some of them to keep (at least one) and re-roll the rest. Continue until you have set all aside. The goal is to have at least one 2, and at least one 4. Your score is the total of the remaining four dice. The maximum score is 24, which you get if you have 2, 4, 6, 6, 6, 6. If you don't have at least one 2 and at least one 4, your score is 0.
Each player takes a turn, and the player with the highest score after everyone has taken a turn wins.
Thanks to Aubrey Clayton for sharing this game and its rules.
Alternately spelled: Two, Four, Twenty four; Two Four Twentyfour