Cucamelons: they're grape-sized watermelons that taste like cucumbers with a tinge of lime. And they're totally easy to grow!
"This is the BEST idea for a space saving, optimum yield cucumber Trellis. This way i can make use of the sides of the beds I've already built" (and do this for melons too - use old stockings to put them in a sling if they get really big... instant space saver!)
Common mallow -- Malva neglecta- A nutritious edible plant (zone 3-8). " All parts of the mallow plant are edible -- the leaves, the stems, the flowers, the seeds, and the roots (it's from the roots that cousin Althaea gives the sap that was used for marshmallows)."