Log Bird Feeder - 23 DIY Birdfeeders That Will Fill Your Garden With Birds (my note: I haven't looked at all of these, but at least one is a terrible idea. The window birdfeeder -- birds could fly into the glass and hurt themselves.
Potato Pot: The most environmentally friendly potatoes are grown this way. in Japan ! Make a potato pot by cutting out the sides of a plant pot and putting it inside another one - this makes it easier to lift the plants out for harvesting.