In the freezer, I've been keeping this ziploc bag full of water to use as an ice pack, and it was soooo hot last night that I decided I'd put it by the window to cool down the air blowing in, because the air blowing in was just as hot as the air inside the apartment.
It worked better than I expected! By morning, the entire area had cooled down by 30 degrees. I never knew that when my mom asked me 'are you trying to air condition the outdoors?' that it was actually a possibility.