Place 1 oz cup inside the larger cup and push it down until it is about level with the rim of the larger cup. Place a stone inside smaller cup to help weigh it down.
Place a piece of duct tape over the two cups.
Repeat until you have your desired number of shot glasses. (You can use different colored Kool-Aid to create an array of colors.)
Place inside freezer for 6-8 hours. (Tip: Set the filled cups inside a loaf pan before placing inside the freezer just in case they overflow.)
Remove from freezer. Fill the small cup with hot tap water, being careful not to let it overflow onto the ice. Let sit for about 30 seconds. Remove inner cup. Run outside of larger cup under warm water until the cup loosens from the ice. Turn over and push gently on the bottom of the cup until the ice pops out.
Fill the shot glasses with beverage of your choice!
Debrief: Ironically, it is the boundaries of the cups and uncomfortable temperature in the freezer that transforms the water into these beautiful ice glasses.