Yeah, I know the title seems unbelievable, but apparently it actually works. I ran across this free ebook (sorry, you have to read it from the website) called Gardening Without Irrigation, which I found here. The author, Steve Solomon, said he lives in the Oregon cascades, which frequently go eight weeks without rain, and his irrigation system is less than reliable. Apparently he's able to grow a lot of crops with no water once they're established and some with only infrequent water or over spray from less-hardy plants.
The key seems to be in spreading the plants far apart (four times as far apart as is recommended on the seed package), getting them established while you still have spring rains at your disposal, and ruthlessly keeping the weeds down. This doesn't work unless you have decent dirt at least a few feet deep (eight or more is best) because rocks and gravel don't hold the water content that dirt does, and hard pan is almost impossible for roots to break through (though he gives tips on how to fix this problem.)
While this wouldn't work on my property--I have to do raised beds because the first hundred-plus feet of ground past my back door is far more rock than dirt--it's an interesting concept. I'd be interested in hearing if anyone else tries it and what they think of it.
There are a lot of other books on gardening, permaculture, and self-sufficiency on the site, so check them out!