Shaun Sperling, whose video of lip-syncing and dancing to Madonna's hit "Vogue" at his 1992 suburban Bar Mitzvah party made himself a You Tube sensation, got another boost: at one of her shows at United Center last week, Madge herself singled out Sperling in the crowd for a brief sing-a-long during "Like a Prayer." Madonna's publicist claims the singer randomly selected Sperling and had no knowledge of the video. You can see Sperling himself in concert this Saturday at Mary's Attic.