Rudimentary evaporative cooling (swamp cooler) air conditioner for temporary relief:
I did this one summer at my first apartment without central air, trying to get to sleep on particularly brutal night of heat (and before I purchased a window unit). It's a holdover measure until you can get circulated air, window unit, etc.
You need a box or floor fan, a bucket or pan, and access to a store that sells bags or blocks of ice. If you have a working freezer, store extra bags of ice in there for regular change out.
Place a bag or block of ice in a pan, or atop the bucket, to catch the melt. Position the fan just behind the block/bag/bucket/pan combination, so that it blows the air over the ice. Situate your sleeping arrangment near this, preferably near or at floor level (heat rising as it does). As the fan blows, it passes the air over the ice, cooling slightly, and drifting near your sleeping area, gently and gradually reducing the nearby temperature to a level that allows you to doze (if not necessarily sleep well). The bucket/pan catches the melt (which you can recycle if the container is clean, or use on houseplants, etc.), and eventually you'll have to replace the melted water with another block or bag, but until more permanent relief arrives, it helps you make it through a miserable night. Note, the effect of the ice on the temperature will be more noticeable in dry climates as opposed to humid ones.
Warrior Poet