Jack Antonoff, Nate Ruess and Andrew Dost of fun. The band’s schedule has been “exhausting,” Ruess says. (Kyle Gustafson/For the Washington Post)

There are times when being in fun. seems like the opposite.

Like when it’s 11 on Saturday morning, and the number of drinks in your bloodstream outnumbers the hours of sleep you’ve clocked on your tour bus, but you’re somehow awake, doing interviews, during which you must explain — for the bazillionth time — why your band chose to spell its name in lowercase letters with a period at the end.

“It’s exhausting,” fun. frontman Nate Ruess says of sudden rock stardom. “Some aspects are annoying, but it’s crazy. We don’t slack or take it for granted.”

Guitarist Jack Antonoff goes into a bobble-head nod. “We know what it’s like to not have this,” he says. “We know 10 years of not having this.”

In a few minutes, the trio will be whisked off to a sound check for a high-noon festival slot at Merriweather Post Pavilion, where it will deliver a bombastic 45-minute set, then hustle to its tour bus and zip up Interstate 95 to Philadelphia for a headlining club gig. For now, the band’s members are in their dressing room, refusing to sit down, talking about how their Queen-size ambitions helped them get “We Are Young,” a hit with a Queen-size chorus, to the top of the charts.

Before it topped Billboard’s Hot 100 in March, “We Are Young” was that song from “Glee.” Then it was that song from the Chevrolet Super Bowl ad. Now it’s that song that’s probably in your head right now: “Toni-i-i-i-i-ight, we are you-u-u-ung.” How about now?

As “We Are Young” unexpectedly soared, the band found itself much busier on the road, cramming radio spots and TV appearances into the gaps of a chain of previously booked club dates — a last hurrah for the loyal fans who have been seeing fun. in small venues since the group formed in New York in 2008. (fun. headlines a sold-out two-night stand at the 9:30 Club on Thursday and Friday.) Although the rooms are intimate, the songs are stadium-worthy. “I’ve watched tons and tons of Queen DVDs, and I just love the thought of a big rock show,” Ruess says.

The band’s sophomore album, “Some Nights,” is thick with refrains that shoot for the nosebleeds with the same melodramatic gusto as “We Are Young.” Nodding to Freddie Mercury, Mott the Hoople, Electric Light Orchestra and Kanye West, the album was overseen by Jeff Bhasker, a producer who has worked with West, Jay-Z, Beyonce and Drake.

Over the course of numerous interviews, the band has burnished a storybook tale about how Ruess persuaded the skeptical producer to get on board by singing him the hook to “We Are Young” after a night of Jameson shots and Ketel One martinis. The band admired the sonic bravura of West’s 2010 album, “My Beautiful Dark Twisted Fantasy,” and hoped Bhasker could intravenously pump some attitude into their songs.

“The only people playing the roles of classic rock stars are hip-hop artists, now,” Antonoff says. “Kanye’s stage persona, and the way he approaches making albums, and the way he wants to be better than everyone else? That’s reminiscent of Freddie Mercury. That’s reminiscent of the Beatles.”

“It’s okay to want to be the best,” keyboardist Andrew Dost says. “It was about trying to be great, and being comfortable with that.”

His line of thinking feels refreshing after years of watching indie-rock bands play down their ambitions. Ruess has a pet theory that indie rock’s half-throttle approach in the 21st century is the direct result of the millennial nu-metal explosion — which is to say, the Limp Bizkits and the Korns of the world made major-label rock-and-roll dreams seem both tacky and absurd. Since nu-metal’s heyday, the trio — Ruess is 30, Dost is 29, Antonoff is 28 — thinks rock-and-roll is too reserved, stylistically and politically.

“You don’t want to say too much; you don’t want to make any noise,” Antonoff says. “You just want to play your music and quietly hate yourself.”

Everyone laughs, but he’s serious. As the band ascended to stardom, it has been vocal in its support of gay rights and hopes to establish a nonprofit organization in support of same-sex marriage. All three members of fun. are straight but say they don’t want to sit on the sidelines when it comes to what they think is the defining social issue of our time.

“We’re firm believers in the idea that if you’re not talking about it, you’re part of the problem,” Antonoff says. “We realize we have an audience, and it would be a real shame to waste it.”

That activist spirit could have rubbed off on Antonoff as a teenager in New Jersey’s politicized D.I.Y. punk scene, where he worshiped local legends Lifetime. Meanwhile, in Phoenix, Ruess was upgrading from a steady diet of pop-punk to the emotive rock of Arizona heroes Jimmy Eat World. Dost’s teenage years in northern Michigan were quieter — the radio, the Beatles and the high school band.

Ruess formed the group in 2008, having crossed paths with Antonoff and Dost on the road in his previous troupe, the Format. They called themselves fun. to avoid a lawsuit from Fun, a Swedish metal group. The chemistry came quickly, and the band released its debut album, “Aim and Ignite,” in 2009.

“You can say something silly or something stupid,” Dost says of the group’s songwriting process. “You never know what it’ll inspire in somebody else. Maybe it’s a slight twist that takes something from being ridiculous to being really neat, or really big, or really powerful.”

Onstage at Merriweather on Saturday, every song the band plays sounds neat. And big. And powerful. “We don’t get to do these festivals, so I want to try something,” Ruess says, then attempts to coach the audience through a call-and-response routine. The gates have just opened, fans are still shuffling in, and the response is halfhearted. Those Queen DVDs made it look too easy.

But Ruess smiles and keeps belting. He knows this won’t be his last chance.