a half gallon of sherbet (any color or flavor)
6 different packs of jello: red, orange, yellow, green, blue, purple
a 9x12 glass pan
Starting with the purple jello, mix one cup of boiling water with pack of jello mix. Whisk for about 2 minutes, then add 1 cup of sherbet. When it's well mixed, pour into glass pan and refrigerate for 1 hour.
Repeat 5 more times with the remaining colors.