51. "Bette Davis Eyes" (2010)
Her kickiest left-field cover, from Speak Now Live. "I'd love to play you some music that I'm a fan of that's come from L.A. – is that OK?" she asks the West Coast crowd, strumming her guitar. "This one came out in 1981 – eight years before I was born!" Virtually nobody seems to recognize it or sing along. Kim Carnes hit Number One with "Bette Davis Eyes," but it was written by the great Jackie DeShannon, the only songwriter to collaborate with both Randy Newman and Jimmy Page. (Page wrote "Tangerine" for DeShannon!) The fact that Swift loves this classic ode to romantic espionage explains a lot.
Best line: "She's pure as New York snow/She's got Bette Davis eyes."