NBC's Brian Williams signs off after a stirring humorous speech.

In a ceremony full of poignancy, the most poignant moment of the 2007 Commencement at Tulane University on May 19 occurred midway through speaker Brian Williams' address.

The award-winning anchor and managing editor of "NBC Nightly News" asked for the house lights in the New Orleans Arena to be turned up, and for all graduates to stand who had done volunteer work in the rebuilding of New Orleans after Hurricane Katrina. As almost every graduate stood -- from the most clean-cut MBA candidate to the flip-flop-wearing liberal arts major -- the groundswell of applause from the large crowd of friends and family brought down the house.

"That's what I mean," said Williams. " This is why we honor you: you came back." Recognition of the resiliency and loyalty of the 2007 graduates permeated the ceremony. The students returned to Tulane after missing the fall semester of their junior year while the university and city were closed in the aftermath of the post-Katrina levee failures.

Among the recognition: From Tulane University President Scott Cowen: "Thank you for coming back to Tulane and New Orleans in January 2006. Your commitment and loyalty helped save this university and this city. Your actions were noted around the world as examples of character, strength and loyalty."

From Class of 2007 student speaker Nadja Tilstra: "We came back not only to study but to rebuild. ... We all grew up hearing that we could change the world, but we have had the unique opportunity to live in a world that has changed us."

And from Williams: "There would not be a Tulane without New Orleans, but I am absolutely convinced that there would not be a New Orleans without Tulane."

There were lighter moments during the two-hour ceremony. Williams recalled a "more innocent time" four years ago when this year's graduates first entered Tulane. He evoked memories of the rock band Korn, the movie Scooby Doo and Napster, and also joked that it was a time "when I had more hair and Britney Spears had hair."

Music always has been an important part of the Tulane commencement, and this year's music had an extra twist. In addition to the national anthem and "Alma Mater" sung by Tulane student Ken Goode Jr. and the soul-stirring jazz of Dr. Michael White's Original Liberty Jazz Band, the crowd was treated to a surprise performance by New Orleans' "first family" of jazz when honorary degree recipient Ellis Marsalis sat in with the band. Marsalis was joined in the performance by two of his sons, Delfeayo and Jason. His most famous son, renowned trumpeter Wynton Marsalis, surprised his father with a videotaped message of congratulation.

Best-selling author John Barry also received an honorary degree.

Saturday's commencement -- the 173rd in university history -- was followed, both at the arena and on the uptown campus, by the diploma-granting ceremonies of the individual schools and colleges.

Suzanne Johnson is editorial manager in the Office of University Publications and executive editor of Tulanian.