Build a better yo-yo and the world will beat a path to your door...or at least droves of yo-yo-crazed people will. Not content with a basic Duncan, Mark Mankiewicz worked with the 3D design wizards at Plano, Texas-based Alibre (where he holds down a day job in customer service) to create a line of aluminum yo-yos that are becoming a must-have for yo-yo experts—and experts in training. The company's name, String Theory YoYos, refers to the yo-yo's essential tether while appealing to "the higher intellectual type of kids who are into physics," notes Mankiewicz. With models such as "Quark" ($99) and "Singularity" ($79), the anodized yo-yos are boldly colored, laser-engraved, and designed for advanced techniques. Meanwhile, having established a company-sponsored pro yo-yo team and a strong presence at competitions throughout the country, Mankiewicz is on his way to having the professional yo-yo world on a string.