A nice Concentration variant by Reiner Knizia. This was one of the first games that my kids absolutely adored. The theme involves finding matching pairs of animals, and it plays similarly to Concentration, but with a few clever design twists that make it particularly appealing for young children. The most significant difference is that on each turn, you reveal a tile, leave it face-up, and then mark it with one of your tokens. Marking the tile gives kids an enormous sense of satisfaction, even when a match is not found. When a match is found, the tokens determine who gets the tiles. The boat tiles, when revealed, cause the animals to be turned face-down again, so memory, of course, is a factor.