This looks like a great tool for Halloween pumpkin carving and a nice gift idea for Dad. The Van Vacter Pumpkin Melon Knife, Black and Stainless Steel
features small grooves for fine carving of surfaces; large grooves for sawing through thick surfaces; ability to easily maneuver with a twist of the wrist; and an ergonomic handle that allows a firm, non-slip grip - looks like a nice option for cutting melons and cantaloupes as well.