Lady Gaga has some rabid fans. At the Bank nightclub in Las Vegas, hundreds of Gaga impersonators took part in “Gaga Wars,” a competition between fans to see who can do the best imitation of the blond singer. “They take it really seriously,” says a spy. “People were going nuts. Especially when [‘Twilight’ star] Jackson Rathbone showed up for his birthday.” Rathbone signed autographs and posed for photos with dozens of Gaga-wannabes.

MORE: POPWRAP’S TOP 10 ENTERTAINERS OF THE YEAR