I use Peconic's watermelon / cantelope mixture and put it in an ice bowl. Find a large mixing bowl, then one about 2-3 inches smaller around. Use duct tape to hold the smaller bowl level with the larger bowl, then sometimes I add something with weight in the smaller bowl to help hold it down once water is added. Fill the area between the two bowls just until the water is about 1 1/2inches from the top, then freeze. If it is going to be really hot outside, I try to have a thicker ice wall along the sides on on the bottom by using a smaller inside bowl. Dip in hot water to quickly release the bowls. Wrap the ice bowl in tin foil and keep frozen until ready to use. This always receives oohs and ahs at a pool party.