Prepare for the Glee cast's Oprah Show appearance with a look back at their most showstopping numbers.
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"Confessions/It's My Life" & "Walkin' on Sunshine/Halo" Mashups
These covers (the men channeled Bon Jovi and Usher while the ladies nailed Katrina & The Waves and Beyoncé) were the first in a long line of Glee mashups. The performances were only heightened by the fact that the students unwittingly took speed administered by—who else?—Teri Schuester (acting as school nurse). In the words of Mr. Schuester, "A mashup is when you take two songs and you mash them together to create an even richer explosion of musical expression." We couldn't have said it better ourselves.