It's the Trending Now Top 5 Countdown for December 5, 2012 - where we gather the hottest and most outrageous must-see YouTube videos hitting the web today and send them all straight to your screen. It’s like watching the best of YouTube — only faster!
From Jimmy Fallon, Mariah Carey, and The Roots performing "All I Want for Christmas is You" to Jay-Z's conversation with an old lady on the subway, we have you covered right here on What’s Trending.
#5: Jay-Z Rides the Subway, Adorably Explains Who He Is
#4: Mr. Burns Explains the Fiscal Cliff
#3: Jimmy Fallon, Mariah Carey & The Roots - "All I Want for Christmas is You" with Classroom Instruments
#2: Neil Patrick Harris & Nathan Fillion in "Doctor's Office" (Neil's Puppet Dreams)
#1: Spartan High School Style