Plant or sow vegetables. The summer harvest should continue for another month or more, but some vegetables have already finished up. Fill vacant spots with year-round veggies like beets, carrots, chard and radishes, though even these may need help germinating in the heat.
An old August trick is to sow seed on the shady or north side of an east-west furrow. Or, shade the seed with window screening or cheesecloth. Sprinkle seeds as often as twice to three times a day to keep moist and help them sprout. Once up, they will grow fine in the heat.