Revel in your roses. Or mourn their passing if they've already succumbed to black spot fungus, sawflies, or Japanese beetles. If you have Knock Out roses, keep deadheading, and they'll bloom right up to frost. If you have the ugly, half-dead-looking roses, vow to replace some of them eventually with resistant Knock Out varieties.
Divide spring-blooming perennials (such as iris and daylily). Dig out clumps, and divide crowded tubers and roots. Shake off excess soil; use your hands to separate the different iris roots (which look like antlers, or maybe lobster claws), and use a shovel or ax to chop large daylily clumps into four smaller clumps. Now, of course, is when you wish you had labeled which color was where. I once had a friend who wrote colors and variety names right on the iris leaves with laundry maker. We all thought he was more than a little obsessive, but now that I find my short-term memory slowly slipping away, I'm a little less judgmental. Dig in plenty of well-rotted compost and a little bone meal so they can be well-fed in their new space.
Plant some fall vegetable plants. It's a wonderful thing when availability finally catches up with demand. In recent years, garden centers and sometimes even the big-box stores have started to carry fall transplants for cabbage, cauliflower, broccoli, collards, and a host of lettuces. Although the weather is hot now, it will shortly start cooling off (I promise) and taper off to freezing around Halloween. These hardy food crops prefer the colder weather, giving us edible parts anytime between 25 days (arugula and mesclun greens) and three months (some of the bigheaded cabbage). Don't plant where cole crops are currently living, as resident pests, especially harlequin bugs, will spread right on over to the tender new babies. Water well, and cover with row cloth to keep the butterflies away.