1. Grill Out!: Utilizing a grill where available is an easy way to keep the heat out of the kitchen and create rich and luxurious meals. It's perfect for meat eaters and veggie eaters alike as the sky is the limit when it comes to grill cuisine. That isn't to say however that you won't get a little sweaty in the process, but it's a small price to pay for having a cool house.
2. Salad Bar: Although the phrase "salad bar" makes you instantly think of sneeze guards and baby tongs, it's a great way to entertain. If you're short on cash, you can even have friends bring their own toppings. The bonus is after all is said and done, the leftovers can be turned into almost any dish imaginable!
3. Bring Your Own ______: Pot luck is an easy way to entertain (and thrifty too), but more importantly it means most the meals on the table aren't coming from your kitchen. There's no shame in asking folks to bring a dish and you can always assign a type of dish (soup, salad, bread, meat) for folks to whip up to make sure all the basics are covered.
4. Single Meat Source + Crock Pot: Making food ahead of time is always a great idea for parties, but more often than not you still have to reheat things before guests arrive. Although that makes things easy, the oven can still heat up your home, even if you're only warming food through. Instead try serving something like gourmet meatball sandwiches, hot dogs, gyros, or tacos as a large amount of meat can be prepared in advanced and the easily reheated in the crock pot which contributes far less heat to your kitchen than the oven or stove.
5. Don't Serve A Main Meal: Just because you're inviting everyone over that doesn't mean you have to plan on having a large meal. Instead, push your party time back an hour (to a time that might suggest guest eat before they come) and change things up a little. Try hosting an ice cream social with all the toppings (guests could even bring a favorite) or potentially a donut buffet with mini milk bottles, which are easy enough to pick up at the store, even last minute!