My kids love to look at a map.  This hangs on the wall in the playroom.  It's inexpensive enough that I am not concerned about damaging, so long as they aren't trying to be destructive.  My three kids play "travel the country" (a game they made up) all the time, using this map.  Not really sure what they're doing, but they're having fun and I here little tidbits about states and cities, rivers, mountains, etc.  so it's a win :)