I really like using songs in the classroom to reinforce grammar points or to teach vocabulary and expressions. I find that songs work especially well with teens so I always ask my students what songs they want to learn the lyrics to. One of my classes chose Mistletoe by Justin Bieber as the Christmas song they wanted to learn. This upload contains a pre-listening worksheet covering some vocabulary and expressions from the song (including a bit of slang and some grammatically incorrect expressions in the song) followed by a listening worksheet (gap fill which repeats some of the previous vocabulary and some additional vocabulary that students should already know). Not included in the worksheet but good to point out is the fact that the song uses the word "reindeers". When students complete the pre-listening worksheet I ask them what the plural of reindeer is. Then, after listening to the song, I ask them what's wrong with "reindeers" and they remember that the singular and plural forms are the same. Answer keys are also included for both worksheets. Enjoy!
Video link: http://www.youtube.com/watch?v=LUjn3RpkcKY&feature=player_embedded