It's the biggest pizza party on the planet. The International Pizza Expo in Las Vegas played host to pie-makers, restaurant owners, and food product innovators from around the world this week. The annual convention features competitions (best pizza-related tattoos, top dough tosser), panels (Stromboli 101, delivery fee debates) and a smattering of Vegas impersonators. But mainly, it serves as a stage for the exotic, odd and incredible pizza trends for the coming year. Check out some of the buzziest toppings from exhibitors at the three-day expo.