I love seeing different styles and methods of gardening that make gardening easier for those that are space, precipitation or monetarily challenged. Here are a couple ideas that I have run across that i think are pretty neat.
natural raised wood garden
What an ingenious idea these folks had. Looks great, seems like it would work and other than the time it takes to build, its free!! One thing that I would change is maybe laying a barrier between the sticks on the sides and the dirt to prevent rot. Then again, if you do that you lose some of the aeration of the soil.. Any who for those with limited resources this is a great way to build a raised bed even if it is a bit of work.. The one pictures is very tall too I would go with a typical foot or two tall bed and simply use larger sticks instead of the pieces of lumber for the braces.
empty plastic bottle garden/planter
This one I really like the concept of I especially like the idea for those with limited water supply, as the way it is set up, the system self waters.In the instructable it says to wire the bottles together as you place them inside the frame once you have poked several holes in it. I say phlooey why make more work for your self. I would make my frame out of logs or wood, make my holes and simple place the bottles in carefully and lay a bit of soil around it to keep it in place. Once all the bottles are in and soil is added the bottles are not going anywhere .
When it rains the water goes in to the bottles and from there waters your plants. If you make a larger box, I would simply add a few bottles in the middle of the planter so that all plants gets water regularly.