They choreographed the entrance well, and danced to the song "Forever" by Chris Brown.
Their video, once it was on YouTube, became popular in only a week, with 10 million views on YouTube. Once the rights holders of the song found out, they could of had YouTube take the song out of the video, but instead decided to put a link on the video to allow people to buy the song.
It worked, and the song itself is popular again, too. Read all about it at: www.googleblog.blogspot.com.