Oh yes! Manhole Masterpiece is great for young'uns! Hard to find though.
Really good adventure-ish (purchasable) titles for that age group include Cluefinders, Humongous Entertainment games (Freddy Fish, Putt-Putt, Spyfox etc), and Dr Brain games.
& David Macaulay's "The New Way Things Work" & "Pinball Science" are especially worthy of note. They are funny and you can't get very far without learning quite a bit :D
There are many free (& educational) fun sites for kids online ~
But free adventure games for children are harder to find. I googled and found these possibilities
Hope something on here is helpful!