Yahoo! Music - It was a greatest-show-on-earth evening, featuring Roberto Cavalli-designed showgirl costumes; a pack of S&M leatherboys led on leashes; a candy-cane-striped poledance routine; a troupe of bullfighters; a cover of Lenny Kravitz's "Are You Gonna Go My Way?" by Melanie Brown; a catwalk march to RuPaul's "Supermodel" by Victoria Beckham; a gymnastic performance of "It's Raining Men" by Geri Halliwell; a medley of '70s disco hits; and enough confetti to probably stuff all the pinatas in Mexico. But the Spice Girls' December 5 Los Angeles concert was still nearly upstaged by a few superstar guests.