His mom, Debra, helped him order the trick-or-treat boxes over the Internet.

And his dad, Benson, helped with motivation. To Benson, getting involved in projects like this is more important than academic work, since he feels it's better preparation for life after school than earning a high grade-point average. "When a child does it the first time and they see success and they get the taste for it, nothing is insurmountable," he said.

But even with friends helping as well, Gregory, 10, had a lot of work to do.

"It was kind of hard," he said. "I had to do everything and organize everything."

He had to make posters explaining what UNICEF does.

He had to visit all the Hokulani classrooms to get the names of everyone who wanted to collect money for UNICEF, the United Nations Children's Fund, while trick-or-treating. He had to impress on them that even a small donation could make a difference.

"One dollar can help a lot of kids and give them vaccination shots," he said.

He collected about $5 trick-or-treating himself, then was in charge of all the money the school collected.

While some people donated dollar bills, most of the donations came in coins, so Gregory took it all to a supermarket to get counted in a Coinstar machine.

After that, he distributed certificates of appreciation to those who helped.

Benson said those certificates, which included coupons, didn't come without a price. A family friend donated them, but now Gregory owes him a favor.

Gregory, who wants to be a backup dancer for a star performer like Beyoncé or Jennifer Lopez, said giving to those less fortunate is important to him. "We have kind of more stuff than the other people, that's why we want to give them some things," he said.

He and his sister are thinking of ways to help even more children.

This year, Kristen launched the program at Mid-Pacific Institute, where she is in the eighth grade, as well as at Sacred Hearts Academy. Along with Hokulani, the three schools raised $1,700.

"Next year, both of them as a team are going to launch it to more schools and potentially to the state," Benson said.

Who helped you? "My sister is mostly the one who helped me. She started everything," Gregory said. "I only had to make adjustments."

What advice would you give to other kids who want to follow your example? "They can start UNICEF (trick-or-treating) at their school, too," he said.