in large mixing bowl place 1-2 2liters of 7-up. take green food coloring and tint green. mix well. place in shamrock shaped ice cube tray. place in freezer til ready to make punch should be frozen when u r ready to use.
in large punch bowl place 2 2liters of 7-up and 1 gallon to 11/2 gallons lime sherbet.
after u put the sherbet in and its malted a bit take and put a tray of green shamrock pop cubes on top the punch will float and the green color might bleed but thats ok. it will look nice.
then as it goes down keep adding pop, green lime sherbet, and ur green pop shamrock pop cubes