WASHINGTON - A day after their beleaguered Dorchester school closed for good, 14 big-hearted Grover Cleveland Middle School students were treated yesterday to a whirlwind tour of the nation’s capital led by two world-champion Boston Celtics.

“We’re so lucky,” said Kerby Joseph, 15, of Mattapan, as she listened to music using guard Tony Allen’s headphones. “After this championship, we get to be with some of the players!”

The students are longtime volunteers at the Madden Senior Center at Kit Clark Senior Services in Dorchester. Every week the 8th-graders visited the senior center to serve clients lunch and keep them company.

“I think it was beautiful,” said Gabe Tuffo, 86, of Savin Hill, who looked forward to the students’ Friday visits.

The kids’ good deeds won them the annual ASSISTS community service project contest, a nine-year-old partnership between the Celtics, Southwest Airlines and the Boston Public Middle Schools designed to encourage students to improve their communities by creating and implementing a service project.

“We did something and we got something back in return,” said Shamalia Barrett, 15, of Dorchester. “I think it’s wonderful - people see (the Celtics) on TV, we get to walk with them, touch them. It’s amazing.”

Yesterday’s tour began with an early-morning Southwest flight to Baltimore. From there, the students took pictures outside the White House, visited the Smithsonian Air and Space Museum and National Mall Monument and met U.S. Sen. John F. Kerry.

“I told him good luck,” said Crystal Walker, 14, of Hyde Park, who got a photo op with Kerry.

The Cleveland program beat 23 other Boston schools with its “Lend-A-Hand” program, the brainchild of Phillip Robinson, a student support coordinator who had been at the Cleveland for 22 years.

“I figured it would be a golden opportunity for them to see how they could serve the community,” said Robinson.

“It’s sweet for the kids. It’s sweet for the school community,” said Cleveland Principal Andrew Tuite, who will take over at the Solomon Lewenberg Middle School in Mattapan in the fall. The Boston School Committee voted in 2005 to close Tuite’s 80-year-old Fields Corner school after years of declining enrollment and lagging test scores. The building is being taken over by the Harbor Pilot School.

The Cleveland students’ good deeds were applauded by Celtics forward Brian Scalabrine, who spent the day touring and joking with the kids.

“There are a certain amount of people in my life who helped me to get where I’m at and I need to give back to them,” he said. “It’s a special thing to help people because not everyone has the opportunity to do it.”