My youngest GS is just 6 and loves playing memory games and others from Orchard Toys. I'll miss it when he grows out of them.
My oldest GC, now 14 and 11, used to love exactly the same games, and will still bring them out to play when we visit. The memory games are good for all ages, my GS often beats us, just like his mother used to when she was his age. Most of the other games we play are games of chance, when you turn over a card to see if there is a match on your "shopping list", so not much skill involved.