Sandkarte
A “Sandkarte” is a Landkarte made in the sand. Take your group to the beach with a couple of maps, a pale, and maybe a rake. Work together on making a map in the sand-make it as detailed as you want (and as time permits)--you can put in mountains, rivers, industrial areas, or you can simply have the outlines of a few countries or the continents. I think this is the most experiential way of learning geography and, if you haven't done it yet yourself, you will be surprised at how much you can learn by actually creating the map with your hands.
Once you have the map made, use it! The applications are endless. Have villagers stand on the map, drive matchbox cars around the map, simulate weather on the map, be animals on the map, put twigs, leaves, etc to represent population, resources, consumption, etc. on the map, invite another Familiengruppe to see your map...