While Rihanna rocked the house on Sunday night at the Video Music Awards — her opening act with Eminem was voted best performance by MTV viewers — her ex-boyfriend, Chris Brown, sulked in a corner at Veranda nightclub in the West Village. “He looked lifeless,” a witness said. “He barely spoke to anyone and refused to take pictures with fans.” On top of that, the disgraced rapper, who was given two free bottles of vodka at the club, stayed for two hours and didn’t leave a tip.