Pie-ology's first and only location is in California. Two more will be up by the end of the year with at least 15 in the next two years.

Pie-ology specializes in personal-sized pizzas that cost $7.50, no matter how many toppings.

Owner James Markham spent hours researching the oven industry until he found this open-flame oven to cook his pizzas at 800 degrees in under 2 minutes. "And conveyor ovens? Really? That gives the customers no theatre whatsoever," he said.

Pie-ology's decor is trendy, yet sophisticated.

The first Top That! Pizza restaurant opened in Tulsa, Okla., in a former Quizno's.

Customers at Top That! Pizza in Tulsa, Okla., go down the line telling chefs what they want on their pizzas.

Top That! Pizza is often packed during lunch and dinner hours.

Pie five pizza co. employees show off the restaurant's freshly made pizza.

Pie five pizza co. welcomed its first customers with a pizza party.

Pie five pizza co. opened its first location in Fort Worth, Texas. Plans are in the works for several more corporate stores before franchising begins.

Mod opened its first location three years ago in Seattle, Wash. It now has four with a fifth on the way.

Mod's decor and culture are inspired by the early 60s fast food combined with the speed and style of the British subculture known as the “MODs" -- young, retro and slightly irreverent.

Mod Owners Ally and Scott Swenson hope to take customers back to a time when "the music was loud, life was simple and style was everything."

Top That! Pizza employees make the dough and sauce fresh every day.

Pie-ology sells individually wrapped Ding Dongs. "I did that so people will walk up and say 'Are those ding dongs? Oh man I haven't had one if those since I was a kid,'" said Owner James Markham. Everyone loves that bit of nostalgia."