Prepare 8-12 cards (or make your own from sturdy paper with simple pictures: fruit, animals, shapes) so every image appears on exactly two cards. Shuffle them and lay them face-down in neat rows on the floor or table.
Taking turns with your child, flip two cards at a time. If they match, that player keeps the pair and goes again; if not, both cards are turned back over and it's the next player's turn. Start with just 4-6 pairs for younger children and add more as their recall improves.
This game trains short-term memory and visual attention, and it also teaches turn-taking and handling winning and losing gracefully.