Video screenshot by Bonnie Cha/CNET

Remember on the first day of grade school when your teachers would ask you to come up to the front of the room and tell your classmates what you did during your summer vacation? Inevitably, there would be tales of frolicking at the beach, camping at national parks, and other cool activities, but we think 9-year-old Caine Monroy just might have the greatest story of all.

A big fan of arcades, Monroy spent his summer creating his own arcade (called Caine's Arcade, naturally) at his dad's auto parts store in east Los Angeles. Using cardboard boxes and the power of imagination, he built true classics like pop-a-shot, mini soccer, and even a claw machine using an S hook and some yarn.

He took care to include such details as a ticket dispenser for each game (Monroy manually feeds the tickets through a slot from inside the box), a prize wall, and gift bags. Monroy even devised a brilliant security system to verify the validity of the monthly Fun Pass, which gets you 500 turns for just $2 (alternatively, you can pay $1 for two turns), so don't even think about trying to cheat at Caine's Arcade.

A true labor of love, Monroy continued to make improvements to his arcade, even though he didn't have any customers. With much of his dad's business going online, there wasn't a whole lot of foot traffic coming through the store, but that didn't prevent Monroy from opening up shop every weekend in the hopes of someone wanting to play some games. Well, that day finally came when Nirwan Mullick walked into Smart Parts and plunked down $2 for a Fun Pass.

Mullick just happened to stop by the shop looking for a used door handle for his '96 Toyota Corolla, but in the end, he walked away with something better. Blown away by Munroy's elaborate cardboard arcade, Mullick returned to the store and asked the boy's father, George Monroy, if he could make a short film about Caine's Arcade. Monroy agreed on the condition that Mullick would bring a few more customers to Caine's Arcade, and from there, it was game on.

Using Facebook and Reddit, Mullick organized a flashmob to show up at Caine's Arcade last October to surprise the 9-year-old. The response shocked the elder Monroy, as he saw responses from all over the world, but no one was more thrilled than Caine Monroy himself.

After spending the morning at Shakey's Pizza playing arcade games, the Monroys returned to the shop to find a cheering crowd and a ton of new customers. On the way home, Monroy later told his father, "Dad, this was the best day of my whole life."

You can check out the heartwarming reaction in Mullick's short film below. (Seriously, if this story doesn't make you smile, then I fear your heart is made of stone.) The filmmakers also set up a scholarship fund for Monroy and are accepting donations on the documentary's Web site.

By the way, Caine's Arcade is still open on the weekends, and Monroy is still adding games, so the next time you find yourself in east L.A. be sure to stop by and play a few games. I know I will.

(Via BoingBoing)