Madonna celebrated her 50th birthday Saturday at a trendy London club called Volstead. Despite lingering rumors of marital strife, the elaborate bash was organized by her husband, Guy Ritchie. "She looks better now than she ever has done," he told the 90 guests, according to Britain's The Sun. Highlights included Madonna's daughter Lourdes serenading her on the piano and illusionist David Blaine performing card tricks.

These celebrities were spotted partying in Las Vegas over the weekend:

•Leonardo DiCaprio tucked into a big meal at Monte Carlo's Brand Steakhouse on Friday before heading into the Bank club at the Bellagio.

•Audrina Patridge (MTV's The Hills), decked out in Betsy Johnson, hosted an event Saturday at the new Christian Audigier the Nightclub at Treasure Island.

•New Kids on the Block celebrated member Donnie Wahlberg's 39th birthday at Jet in the Mirage on Saturday.

"I ended a relationship to be alone, because I don't want to waste somebody's time if something's not right." John Mayer, on his breakup with Jennifer Aniston

Ginger Baker (Cream, Blind Faith), 69 ... Gerald McRaney, 60 ... Martin Donovan, 51 ... Clay Walker, 39 Karli Osborn (SHeDaisy), 24