It was above 90 degrees several days in a row this summer and we don't have air conditioning, so the baby and I mostly sat in front of fans on those days, and when it came time for dinner I wanted something cool. This Chilled Zucchini Soup from Food and Wine was perfect on those days.
sesame yuba noodles (so much protein!). It does require heat, but that part is short and totally worth it for the flavor it adds, even on a disgustingly hot day. And if you don't have purslane or arugula, don't fret--the greens are just a garnish. I did have purslane (it grows as a weed around here and overtook two of my pots of dill in the garden), but next time I make this soup I'm just going to have it (or a different green) on the side.