Here it is, getting on in the summer, and you just never found the time to find a free patch of dirt and start your new veggie garden as you always meant to! But never fear, August is still planting time - and there's lots you can grow!
Okay, it's too late to grow tomatoes or start corn, but there's still time to grow a crop of turnips, scallions, radishes, lettuces, and all kind of greens: endive, kale, collards, spinach and chard. In the heat of the summer, most of these should be planted in partial shade - they'll go to seed in full sun. The lettuce and the radishes, you should be able to plant in successive plantings a few weeks apart, and get several rounds of crops off before the summer comes to a close.
Plus, now's the time to start a seed bed of your winter crops - kale, cauliflower, broccoli, cabbage, and onions. You start them all from seed in one small area, then as the rest of your garden peters out in the fall, transplant the winter seedlings to the rest of your garden.
From then on, they'll grow for another 6-8 weeks, depending on the weather, then basically go dormant through into late January or so. Then, in February-March, you can start eating fresh food from your garden again! We really do get a good nine months plus of garden food in a year!
You can also consider what perennials you want in your garden - raspberries, blueberry bushes, currants, and so on, and plan to plant them in the fall.