By Brian Maass

AURORA, Colo. (CBS4)– When a group of nearly 30 diners descended on her section of a Village Inn restaurant in Aurora early Thursday morning, server Ayla McMaryion figured it would be a busy hour taking orders and delivering eggs, bacon, and pancakes. Instead, she had no idea what was really in store.

The group was part of an underground movement known as the “Shock and Claus” breakfast that has been secretly surprising restaurant servers around Denver with massive cash windfalls since 2015.

When the diners left, each left a $100 tip on top of their bills, leaving McMaryion stunned.

“Are you guys serious?” asked the 20-year-old server when she realized she had been left tips totaling $1,700.

“This is the best day ever… you guys have no clue,” she said as she hugged and thanked the group as they left the restaurant.

She said she would use the money to help pay for college tuition and car payments.

The group gave another $300 to Mario Jones, a cook in the kitchen. He said the tip was the equivalent of two days salary.

“I think this was amazing, I’m feeling blessed and very happy and love everything they did for me. I hope they have a Merry Christmas and a Happy New Year!” said Jones.

The scene was repeated throughout Thursday at restaurants in Denver, Englewood and Aurora as groups of generous diners made their rounds. Many learned of the event through social media and friends. They gathered and left thousands of dollars in tips for stunned servers like Lou Mondragon at the 20th Street Café in Denver.

Mondragon has worked at the family-owned restaurant for 27 years and was behind on her rent. The group left her $2,890 in tips.

“It is so awesome, thank you Lord, he blessed me, thank you,” said Mondragon as she hugged the diners.

She said she was behind on rent and car payments so the holiday cash was a godsend.

The annual event is in its fourth year after it was started by a loose-knit group of Denver metro area businessmen who simply wanted to be better people and be better members of the community.

“It’s a simple thing, it’s a small thing but you get a bunch of people together and you have an impact on someone’s life,” said Dudley Morton, one of the founders of the Shock and Claus event.

It began with Morton and a group of friends leaving $4,000 in a tip for a server at a Perkins restaurant in Denver in 2015.

“She came over and said, ”I’m a single mother with three kids and I was literally praying for a Christmas miracle and you guys showed up.”

Since then, the event has grown through word of mouth and social media.

“We live in a day and age where we don’t always hear good news,” said Morton, ”and if we can inspire some people through what we are doing to do nice things for other people, that’s amazing.”

It was an amazing morning for Blanca Arguello, a server at an Englewood IHOP. Her group of 22 diners left her a $2,200 tip.

“That’s amazing. I never had that happen before,” exclaimed Arguello.

She said with four kids at home, the unexpected cash would help her catch up on bills.

“We weren’t expecting this, thank you so much,” she said as she exchanged hugs with the departing patrons.

Morton is hoping the Shock and Claus concept spreads across the country. He says it’s simple to do. He says just gather a group of friends and add whatever extra you can to the bill. It doesn’t have to be $100. And he points out it doesn’t have to happen on a particular day.

”You can do this anytime, anywhere. The beauty is in its simplicity. Let’s bring a bit more humanity into our lives and be better people in our communities.”

CBS4 Investigator Brian Maass has been with the station more than 30 years uncovering waste, fraud and corruption. Follow him on Twitter @Briancbs4.