Power crowd mingles at Graydon Carter’s pre-Super Bowl party

Uber chief executive Travis Kalanick’s girlfriend, Gabi Holzwarth — a.k.a. The Violin Girl of Silicon Valley — grabbed a string instrument from a mariachi player at Vanity Fair editor Graydon Carter’s pre-Super Bowl party Saturday.

“She treated incoming guests to an impromptu solo,” a spy said.

Also at Carter’s tech-mogul-heavy bash, Alex Rodriguez chatted with Anne Wojcicki, ex-wife of Google co-founder Sergey Brin, as well as hedge-funder Paul Tudor Jones.

January Jones and Amy Adams posed in nearly identical white dresses (Adams had a Broncos manicure).

Cowboys owner Jerry Jones “kept his eyes open for investment opportunities,” said a spy in the room, where former Twitter CEO Dick Costolo, Yelp CEO Jeremy Stoppelman, Airbnb co-founder Brian Chesky, Zynga’s Mark Pincus and YouTube CEO Susan Wojcicki schmoozed.

Also at the bash, co-hosted by Jon Bon Jovi, were Adriana Lima, Seal, Nick and Joe Jonas, Giants co-owner John Mara, Redskins owner Daniel Snyder and Eagles owner Jeffrey Lurie.