"It's equivalent to the Wright Brothers experiment," ?uestlove say of jamming. "There is no room for a crash." It is the day after the third annual holiday party for his Okayplayer web community, a jam session of sorts, and he is walking the grounds of his workplace, NBC headquarters 30 Rockefeller Plaza, feeling kind of meh about it. Soon after the Philadelphia-based hiphop crew was handpicked to be the Late Night with Jimmy Fallon house band, they rather masochistically revived an old habit, weeknight jam sessions.

The pressure to "make a magic moment" and a healthy dose of exhaustion drove the crew to recently halt the exercise. Long days on the Fallon set in New York City, where most band members commute from Philadelphia, turned into long nights improvising in a Manhattan club. It was a twist on their early days hosting jam sessions in Philadelphia for hungry hiphop and R&B aspirants—Erykah Badu, Musiq, Bilal, Mos Def, Talib Kweli, Jill Scott—who have all since secured spots, in some cases tenuous, in the alterna-hiphop and soul pantheons. "We didn't meet an artist once they were on Pennsylvania Avenue on the Monopoly board, or Park Place or Boardwalk." ?uestlove reflects, "We had them when they were on Baltic Avenue, Mediterranean Avenue—the projects properties on the Monopoly board."

Their Fallon gig has got to feel a little like Pennsylvania Avenue, if not Park Place, to extend the board-game metaphor. Nightly, the crew conceives and plays appropriate walk-on music for their guests under the goofily admiring gaze of boss Fallon. Mos Def has sat in with the band on a few occasions, Talib Kweli too. They've backed musical guests like 50 Cent, Paul Simon, and Jimmy Buffett with punchy arrangements, and they hosted a yacht rock reunion, "Ride Like the Wind," with Michael McDonald and Christopher Cross, for goodness sake.

The band is exciting to watch and hear, unlike Fallon's enduring unfunniness, and the grandness of the stage is not lost on the Roots. ?uestlove is still awed that his band had their own float sandwiched between the Peanuts gang and SpongeBob SquarePants in the most recent Macy's Thanksgiving Day Parade and that the band took part in the lighting of Rockefeller Plaza's Christmas tree with 30 Rock's Jane Krakowski. ?uestlove emphasizes that this time last year the Roots were playing before 14,000 in Paris, France. "Who knew, who knew that exactly one year later I would have a white-collar job at 30 Rockefeller Plaza," he says. "Who would have called this moment?"

The Roots are preparing for the release of their ninth studio album, How I Got Over, in 2010. It should have dropped this past October but the grind of their day jobs didn't allow the meticulous unit the time they felt was necessary to satisfy their high standards and their notoriously picky fanbase. Talib Kweli has called them "Okayplayer haters," but ?uestlove insists it's "the wrath of their madness" that makes [him] work harder." ?uestlove attributes the new album's churchy sound to keyboardist Kamal Gray manning a Hammond B3 organ instead of his reliable Rhodes, creating a sound evocative of hiphop's growing, pain-inflected moment of global economic crises and violence.

"The theme of How I Got Over in its current state is the story of struggle and elbow grease," ?uestlove explains, and from the sound of the title track, which debuted on Fallon in June, frontman Black Thought is increasingly playing the role of funk sanger alongside searing rapper. (Tariq Trotter, as Fallon refers to him, does a whole host of singing on the show, and his well-toured cover of Bobby Womack's "I Can Understand It" is impossible to shake.)

There is no exultancy in the concentrated spotlight, though, just hunger for more opportunities for the Roots to exercise their unparalleled sustained creativity. Like for example, successfully integrating a sousaphonist, the indefatigable Damon "Tuba Gooding Jr." Bryson, to a hiphop band.

?uestlove forecasts a kids' album in their future in a They Might Be Giants vein; a musically rigorous album that wouldn't condescend to children. Most of the Roots are parents after all, and they saw the Fallon gig as a step toward greater stability. With Roots guest spots on children's TV show Yo Gabba Gabba!, ?uestlove has observed firsthand how much their demographic has shifted. He finds it hard to envision a Roots fan under 19 these days, yet remembers that a decade ago high school and college students would rush band members in public and gleefully introduce them to their parents. "Nowadays," ?uestlove says, "the parents are running up to me like, 'Oh my god! Kids, this is ?uestlove and the Roots.' The kids are like, 'huh.'" All part and parcel to growing older and getting over gracefully.