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.
Creating a self watering garden - use drip irrigation and mulch and never water your garden again!
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.