I'm a 'Shark Tank' superfan who's always dreamed of being on the show. Here's what it's like to join 600 hopefuls in an open casting call for the hit series

Patricia Arder, the founder of PillowPeepers (glasses that allow you to sleep on your side comfortably), told me she hadn't even rehearsed her pitch much since she knew her business so well.

Joseph Chiodi, founder of the Famous Meatballers (frozen meatballs made from an authentic Italian recipe) said he wasn't nervous because he knew this was a "shot in the dark."

He'd also already won first place on Rachael Ray's seventh annual "5-Alarm Cook-Off Challenge," which featured New York City firefighters like Chiodi.

One of the first founders I met was Katey Evans, the vice president of sales and marketing at The Frozen Farmer. The company turns produce (including "ugly," or misshapen, produce) from their third-generation family farm into ice cream and sorbet.

The Frozen Farmer had already received a video from Bethenny Frenkel saying she'd be willing to invest if they made it onto "Shark Tank." Evans had flown in from Delaware with her two young daughters (one dressed as a strawberry) to pitch.

Marius Morariu, meanwhile, is the cofounder of beauty and wellness brand Tracie Martyn. The company has been around for about 20 years — "before it was cool to be into wellness," Morariu told me — and has a shop on Fifth Avenue in New York City. They offer Rihanna's favorite facial. (Still, I'd somehow never heard of them.)

Morariu said he'd just found out about the casting call that morning, and decided to give it a shot.

Before the doors to the Javits Center officially opened, a woman bounded over to me bearing donuts — specifically, Ohketo Donuts.

Brennan Terry launched the company, which makes "guilt-free" pastries geared toward people on the ketogenic diet, just six months ago. But she said she'd gotten encouraging feedback so far.

"We're really excited to be able to pitch to 'Shark Tank' and to see where it can take us," she said.

I introduced myself to two brothers dressed in (what I thought were) tuxedo shirts. As it turns out, they're the founders of The Magnetic Button by LI Solutions Inc.

The Magnetic Button turns standard shirt buttons into snaps so you can get dressed more easily. David Puglia told me he'd come up with the idea 20 years ago, after he had an operation that made it difficult to use his hands for things like buttoning up a shirt.

To me, this product seemed hugely innovative and useful — but if you'd left me in a room to think for the next century, I never would have come up with it.

Once the first batch of entrepreneurs had filed into the Javits Center basement, casting director Mindy Zemrak ran down some rules and best practices.

Among them was the one thing you should never say to the casting agents: "If I can get 1% of a $20 billion industry..." If you've watched even a few episodes of "Shark Tank," you know this is a line that many entrepreneurs repeat (though it's unclear how persuasive it is).

Instead, Zemrak, said the casting agents want to learn about you and your company. "'Shark Tank' is 50% about your business or your product and 50% about you and your backstory," she said. If you took out a second mortgage or depleted your kid's college fund, for example, they want to hear about it, so they know you're "all in."

I thought Zemrak's guideline about telling your story made sense. Glasses, meatballs, sorbet, or buttons — by far the most interesting thing about each company was the people behind it, who'd taken a creative business idea and run with it.

Just before I left for the day, I met the Knoetgen family, who was pitching Love of Country Clothing, a "patriotic clothing line" made in the US and dedicated to those who serve in the military, fire, and police departments and EMS.

Joseph Knoetgen, who is an active duty medic in the air force, told me he and his family have a personal investment in the company. "It's not just a line; it's not just a brand or a company," he said. "It's what we believe in."