12-liter bottle Lemon-Lime Soda (Can also use ginger-ale. Use diet soda if diabetic.)
1/2gallonLime SherbetAny flavor works, but lime has the best "slime" color effect!
Instructions
Scoop sherbet into punch bowl or individual glasses. Pour soda over the top.
Notes
Variations on this include adding 12oz limeade or a large can of pineapple juice. Both of these will increase the potassium content, so if you're needing a restricted potassium diet, be careful about quantities.