Dear skippy,
Dig a big hole in your back yard. Put a big bucket in the middle of the hole.
Put a sheet of clear polythene over the top of the excavated hole, and weight the sheet round the edges with more stones so that the sheet has no tendency to fall into the hole.
Place a small stone on top of the sheet directly above the centre of the bucket below. The sheet will form some kind of inverted cone.
The general idea is that ground moisture will be heated inside the hole (due to in-coming solar radiation trapped by the polythene sheet), and will condense on the underside of the sheet. It will then drip into the bucket awaiting your collection.
If you are feeling brave, you could attempt to augment the ground moisture with "grey water" from your house, but I'm not sure about the possibility of bacteria making the the leap into your bucket.
Ah well, just a thought....
Best wishes
Martin