This is from the USA and the world of professional basketball. The Dallas Mavericks beat Miami to win the 2011 National Championship (NBA Finals). The Most Valuable Player (MVP) was voted Dirk Nowitzki # 41 (he is from Germany) but is a veteran player for Dallas, Texas. After their championship win he leads the other players and the crowd outside in singing a few bars of "We are the Champions." He's not a great singer at all, but he's a hell of a player and leader: each time he is praised he gives credit to the team and teamwork and each time the team has been criticized he cites his own weaknesses. So here they are enjoying their moment with the fans and you can see their trophy hoisted on the left of the screen. link
Also here is an interview, post game, with Dirk. It's also his birthday today as well, so 20,000 fans sing happy birthday to him at the end of it. link