Creating a self watering garden - use drip irrigation and mulch and never water your garden again!
If you succession plant, sowing seeds every week in a few different planters, you'll create a supply of greens that will be ready in a steady stream all summer. Greens like these are also good for sheltered decks or patios that don't get much sun, since lettuce doesn't like a lot of heat and will grow better during the summer in cool shade.
Make a self-waterer for pots: Cut the bottom out of a 2-liter plastic bottle. Remove lid, cover opening with a small piece of gauze, secured with a rubber band around the neck of the bottle. (This keeps the soil from forming a plug in the opening.) Push neck of bottle into soil; do this near the edge so the bottle can rest against the pot. Fill the bottle with water. For small containers (such as houseplants) Use small plastic beverage or cough syrup bottles.
oooh genius repurpose! Old filing cabinet + spray paint = raised planting bed. I might add that packing peanuts make a good filler for the bottom of deep containers, then just put your potting soil on top. Makes for good drainage too.