Unlike many NBA owners, Mark Cuban is more than just a rich dude. He knows how to promote himself, whether that involves starring in reality shows or acting like a jerk to draw attention to one of his many business ventures. Yes, I understand that those two things aren't mutually exclusive.
He is a showman. Unfortunately, he can't sing at all. An intrepid fan captured Cubes singing Prince's classic "Purple Rain" at a karaoke bar, and you can watch and listen above. Nothing else happens in the video. Enjoy these five minutes of Cuban singing a song you love in a way that makes you never want to listen to it again.
At the risk of drawing too many conclusions from this song choice, I think it sends a pretty clear message about Cuban's mindset during the lockout. You see, he is not terribly upset with the league office for giving him bad national TV games, because he knows the team needed to prove itself as a worthy champion first. Now he has their respect. Also, he wants Mavs players to know that he's sorry if he acted like a jerk before. He values their contributions and cares about them. He wouldn't purify just anyone in the White Rock Lake spillway.
There's no video, but I'm just going to assume that after this song ended Cuban immediately followed things up with "I Would Die 4 U" and "Baby I'm a Star." Then he was kicked out of the bar, because even billionaires shouldn't hog the mic.