Hee hee, this is fun but start early because it takes all day!
5 boxes (8 oz.) jello in red, orange, yellow, green purple
2 cans evaporated milk
Purchase the 8 oz. boxes, but only prepare half of the box at a time.
Layer One: 1/2 box red jello, mix with 3/4 c. boiling water, then when dissolved add 1/2 c. COLD water
Let this set up in the fridge for at least half an hour.
Layer Two: remaining half of red jello, mix with 3/4 c. boiling water, then when dissolved add 1/2 c. evaporated milk
Repeat with the rest of the colors.