As two screens projected the Rev. Dr. Martin Luther King Jr.'s "I Have a Dream" speech at Girard College on Monday, a group of Girl Scouts stood alongside a table with an assortment of socks on it.

"We want to collect socks and donate them to a local shelter where women stay with their children," said Melissa Theron, troop leader of Philadelphia-based Girl Scout Troop 94503. "Our motto is to help people at all times. That's why this is so special to us."

Theron and her group of 30 Girl Scouts were participating in the Greater Philadelphia Martin Luther King Day of Service during Monday's federal holiday honoring the late civil-rights leader. The day coincided with President Obama's public inauguration ceremony for his second term.

"It's a powerful day when we inaugurate, again, the 44th president of the United States, and we celebrate the nation and democracy, and at the same time we are celebrating the legacy of one of the greatest Americans in Dr. King," said Todd Bernstein, founder of Philadelphia's service day.

"Dr. King was a man of action 365 days a year, and this is really that springboard opportunity for people to give back," Bernstein said.

The signature event was at Girard, where 4,000 volunteers participated in civic engagement. A jobs fair was also hosted on the grounds of the school, founded in 1848 to provide white orphan boys with a quality education. King rallied a desegregation movement at Girard in 1965, paving the way to the school's integration and opening to girls.

King delivered his "I Have a Dream" speech 50 years ago in the nation's capital. On Monday, it played a prominent role in the Philadelphia Orchestra's 23d annual Martin Luther King Jr. Tribute Concert at Martin Luther King High School on Stenton Avenue.

A nationally acclaimed storyteller, Charlotte Blake Alston, read King's speech as the orchestra performed works by composers including Ravel and Beethoven before a crowd of 700 people.

Shoba Babu, a student at Central High School, spoke on King's legacy, saying his "words still resonate." The Philadelphia All City Choir performed as well.

"So far it's beautiful," said Bill Crawford, 42, as the concert broke for intermission. He complimented Alston's narration.

Bernstein hosts the day of service as president of the nonprofit organization Global Citizen. He said Philadelphia's is the largest King's Birthday event in the nation, with more than 110,000 volunteers serving in 1,500 projects throughout the region.

"I think this is the best way to honor Dr. King and bring people together," said Marcia Martin, vice president of Gateway Health Plan, one of the event's sponsors. Gateway's volunteers were making get-well cards for children.

High school volunteers from the group BuildOn participated by using social media to collect dress suits to be donated to people in need of professional attire.

"Our students do volunteer service every weekend, so it's great to be around a lot of people doing service," said Crystal Collins, BuildOn's program coordinator.

At Gompers School in the Overbrook section, City Year Greater Philadelphia and volunteers from other groups painted indoor murals.

Among the volunteers was Jessica Brown, 24, an alumna of James Madison University. She was painting a mural of two shoes in a sky-like background with the proverb "Never judge a man until you have walked a mile in his moccasins."

City Year operations coordinator Rebecca Tyrrell, 25, said it made her "proud to be part of an organization that united the community."

Theron, the Girl Scout leader, said the troop's efforts to collect and donate socks served a need: "Who doesn't need a fresh pair of clean socks?"