It’s the Trending Now Top 5 Countdown for September 17, 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 an unexpectedly stunning grocery store karaoke performance to the best way to flash mob during a brutal test, we have you covered right here on What’s Trending.

#5: Caine’s Arcade 2: The Global Cardboard Challenge

#4: “The Worst Test” – An Engineering Flash Mob

#3: Banned iPhone 5 Promo

#2: Ben Folds Five and Fraggle Rock “Do It Anyway”

#1: A Random Girl Steps Up to a Karaoke Machine and Floors Everyone

One More Thing!: REMIX – Honey Boo Boo – GO GO JUICE

For daily YouTube Trends and celebrity interviews, watch us every weekday at noon PT/3 pm ET on YouTube!

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