Odd World

Odd World immerses players in a game universe where collecting the most planets is the path to victory. However, you score a planet only if you have an odd number of cards showing it.

To set up, shuffle the cards, then split them into two decks. The "top" of each card shows two planets numbered 1-9, say, 3 and 6, and the "bottom" of the card will show either 3 or 6.

On a turn, take the top card of either stack, then either keep it or give it to another player. Whoever has the card now flips it over and adds it to their collection. Keep playing until all the cards have been claimed or someone has at least one card of each number 1-9. To score, for each numeral, if you have an even number of cards, discard those cards. Count how many cards remain; whoever has the most cards wins.

Crazy Birds plays the same as Odd World, but with players now trying to collect birds instead of planets.