Ray Parker Jr. performing "Ghostbusters" at the ASCAP “We Write the Songs” concert on Tuesday night. (Abby Brack Lewis)

Ray Parker Jr. had managed to command the ear of Congress for a few minutes — with a frisky, rump-shaking performance of his 1982 hit, “The Other Woman” — and now he had a message to share. About the time a producer hired him to work up a little riff for a movie, and, well, they liked it so much, he turned it into a song; maybe you’ve heard it?

“I think we’re at 30 million records now,” the R&B man told lawmakers and other guests at an ASCAP performance at the Library of Congress Tuesday. “And toys, slot machines. . . they pay well, keep my kids in college. Thank you, Congress, for intellectual property!” Cue the opening riff of “Ghostbusters.”

Sorry, congressfolk: There’s no such thing as a free concert.

Valerie Simpson (Abby Brack Lewis/Library of Congress)

The annual charm offensive from the trade association for songwriters and music publishers is one of the more popular invitations on the Hill (Nancy Pelosi, Steny Hoyer, John Conyers, Marsha Blackburn and Saxby Chambliss among the many who turned out), but the toe-tapping comes with some buttonholing: “How precious copyright is!” cheered ASCAP prez and “We’ve Only Just Begun” songwriter Paul Williams.

The appeal of the show is hearing hits sung not by the singers you know but by their often more obscure writers. So it was a diminutive 80-something, Irving Burgie, grooving around the stage to Harry Belafonte’s “Day-O.” And a wiry middle-aged white guy in a suit, Dino Fekaris, belting out the opening lines of Gloria Gaynor’s “I Will Survive.” Only one scribe cheated: Tom Whitlock, handing off the mic to Terri Nunn, the sultry Berlin frontwoman who made his “Take My Breath Away” an ’80s hit — but hey, she’s a songwriter, too, so give them a pass. (And she holds no grudges against the writers, who by law reap the big royalties instead of the singers. “What's important to me is that music is valued,” she told us. “If that goes away, the music will too.”)

Where do they come from, these songs? “I wrote that on Valentine’s Day, for my wife,” drawled long-haired Chris Stapleton about country hit “Your Man” (the baby lock’em doors tune that was all over “American Idol” last year). Stephen Schwartz asked his daughter what she’d say if she knew she’d never see her best friend again; her answer shaped the lyrics for “For Good,” the showstopper finale of Broadway’s “Wicked.” “I just sat on my bed and I came up with this chord and I played it for days and days,” said Stephen Bishop about 1977’s “On and On.”

Melanie (Abby Brack Lewis/Library of Congress)

Not a dry eye in the house for Valerie Simpson, widow and songwriting partner of Motown legend Nick Ashford, who died last summer, as she described one of their big hits.

“People think it’s a love song,” she said. “Actually, it was Nick Ashcroft walking down streets of New York City and looking up at the buildings of Central Park West and wondering if he’d be a success. . . Those buildings were like mountains.” Then she began a heartfelt “Ain’t No Mountain High Enough.”

As the audience, moved, rose to its feet, Simpson brought home the message: “This song has spawned memories for us. Great memories, y’all — and great royalties.”