Would you like a frosty beverage?
Hot day? Can't keep the ice in your drink from melting and watering it down?
Take two stainless steel mixing bowls, one large and one that just fits inside of the first one, and put them together like that. Fill the smaller 3/4 to 4/5 with ice, leaving the bowls with a pocket of air between them. Use that to keep your drink cool.
It won't last forever in the sun, but with the insulation that's just been created with one bowl inside the other it will last longer than the ice would in your drink. Inside the house it'll last for hours.