By Steven Louie, NBC News
LOS ANGELES -- On Mission Road in East Los Angeles, out in front of an auto repair shop and an old junkyard, there's a stray marble still lodged in the crack of the sidewalk. Detritus from bang snaps is strewn here and there, and the pavement is flecked with bits of old cardboard. It was here, more than a year ago, that 11-year-old Caine Monroy first stepped onto the world's stage, and it was here that he decided to close his arcade for the last time.
It all started with some tape, a cardboard box and one child's imagination. Caine built his arcade with some leftover materials he found in the back of his father's auto repair shop. First there was a basketball game, then a soccer game and a claw, each intricately designed. By the end of the summer, George Monroy's shop had been transformed into a cardboard emporium, but Caine still didn't have any customers.
Then filmmaker Nirvan Mullick came in to buy a door handle, and Caine's life changed forever.
"For adults like me, Caine's arcade brings you back to your childhood," Mullick said. "That's what happened to me when Caine crawled into the box and pushed out the tickets. I was a nine-year-old kid again."
Mullick bought Caine's first "funpass," produced a web film about the boy's creation, and the story went viral. Soon there were lines down the block with visitors from across the world, and news crews were vying for access to the young star. Mullick set up a scholarship fund for Caine, which has raised more than $235,000.
But Caine didn't stop there. He's since become the youngest entrepreneur to speak at USC's Marshall School of Business, he's been featured in magazines, he's spoken on panels, and he even got his picture on a billboard.
"I'm really proud right now, I mean, this just came out of nowhere," said Caine's father, George Monroy. "He was just messing around with a little basketball hoop and putting boxes of tape together, and he changed the whole world."
Caine's arcade grew into a global cardboard challenge, through a non-profit called the Imagination Foundation that inspires kids around the world to think outside the box.
Each year the cardboard challenge culminates with a Global day of play to coincide with the anniversary of the flash mob that made Caine's day back in 2011. Last year children from 41 countries participated, from Sri Lanka to Ireland to South Africa.
Cinda Lester is a mother of two and PTA board member at El Sierra Elementary School in Downer's Grove, Ill. She organized a cardboard challenge for roughly 300 students last year.
"I saw the Caine's Arcade video, and I fell in love with it," Lester said. There were more than 50 entries for the global day of play at El Sierra, including foosball tables, robots and claw machines.
As an architect, Lester appreciates the value of hands-on creativity.
"Not only can they say what they've learned, but they can show what they've learned by building it," Lester said.
And here on the streets of East Los Angeles, where the boxes are now neatly stacked away, the germ of one child's idea has grown into a movement. While Caine is closing shop and moving on, his arcade will live on in the imaginations of children around the world.
In the words of Caine Monroy, "It doesn't matter how old you are, all you need is cardboard and your imagination."
This year, on October 5, the Imagination Foundation will hold its second annual Global Day of Play. It’s the culmination of the month-long cardboard challenge that hopes to bring together one million children in 70 countries, sharing their cardboard creations and celebrating creative play.