The previously mentioned "space saving" zucchini, with all its mass, it's prickly leaf stalks and very large leaves (several feet across, easily)
DID YOU KNOW... Corn is a member of the grass family? (So are other cereal grains, like wheat, barley, oats, rye, and rice.) The next time you're driving down the highway or along a country road, take note of the grasses growing alongside. If the mowing crews haven't been through yet and the grass is tall enough, you might be able to see the resemblance between some roadside grasses and corn stalks. (Keep your eye on the road, though, too - I don't want to be held responsible for any driving accidents!)
Rhubarb (this was donated by one of our neighbors, and has managed to survive several thorough munchings by the deer)
We didn't choose the purslane, it chose us. Considered a weed by many (including me for several years), it quickly forms a dense mat of vegetation if left unchecked. It seems to be much more appreciated in other countries for its use as a fresh vegetable/herb (like Turkey, Greece and Mexico), but I have seen it for sale at our local farmer's market. But we don't need to buy it, because it grows very readily in our garden.
I'll tell you more about it tomorrow.