The machine Artie uses is a real invention. The ReWalk was invented in Israel.
The first song in this episode is "the most wonderful day of the year" sung by the toys in the island of misfit toys. That's what Sue referred to the kids in the glee club in the first episode.
This is the first Christmas duet between Kurt and Blaine. They would continue it through the rest of the Christmas shows.
On the Christmas CD "Glee: The Music, The Christmas Album", Dianna Agron's (Quinn) lines in "The Most Wonderful Day of the Year" are being sung by Chris Colfer (Kurt) instead; everyone else sings the parts they had onscreen.