CBS' 'Big Bang Theory' tops ratings for first time this season It's the revenge of the nerds: "The Big Bang Theory" was the top-rated TV show among young adults last week. Last week's episode of the CBS sitcom about the lives and loves of science geeks was No. 1 among adults aged 18 to 49 for the first time this season, according to Nielsen. Actually, it tied with Fox's "American Idol," but first place is first place. Partly as a result, CBS ended up tied with Fox in the 18-to-49 demographic, the one most advertisers watch. "Idol" used to be invincible in the ratings, but those days are long gone. This season, "Idol" has won outright just seven of 16 weeks. It failed to win or tie during weeks that included the NFC championship, the Super Bowl, the Grammys, "The Voice," the NCAA basketball tournament and now "Big Bang." What do you think of "Big Bang"? "The Voice" reveals season 2 winner Kentucky Derby ratings up as women tune in Stephen Hawking turns up on "Big Bang Theory" Photo: Jim Parsons and Mayim Bialik in "The Big Bang Theory." Credit: Sonja Flemming / CBS