They're Taking The Hobbits to Isengard is a famous internet meme comprising a song/video remix originally posted at a flash website Albino Blacksheep by Erwin Beekveld. It was made by mixing clips from the movie The Two Towers and mainly shows Legolas shouting his iconic line, "They're taking the hobbits to Isengard!", together with spoken material by Celeborn and Gollum and reaction shots by Aragorn, Galadriel and Samwise Gamgee.
Peter Jackson and Orlando Bloom got such a kick out of the song that on Bloom's last day of filming for the Hobbit trilogy, Jackson shot a video of Bloom "covering" the song on his phone.