Steve Ballmer is a CEO of Microsoft and a very intense personality, as you can see from the videos below. In 2008, Mr. Ballmer was ranked the 43rd richest person in the world, with an estimated wealth of $15 billion.
Steve Ballmer shows his excitement at Microsoft 25th Anniversary by performing what became known as "Monkey Boy dance."
"Developers, Developers, Developers!" Steve Ballmer shows how important the applications developers are to Microsoft.
Wikipedia describes those "viral videos":
"Footage featuring Ballmer's flamboyant stage appearances at Microsoft events have been widely circulated on the Internet, becoming what are known as "viral videos". The most famous of these is commonly titled "Dance Monkeyboy", it features Ballmer dancing and hopping around while verbally screeching and screaming erratically on a stage for about 45 seconds after being introduced at a Microsoft employee convention. Another video, captured at a developers' conference just days later, featured a visibly sweat-drenched Ballmer chanting and shouting the word "developers" fourteen times in front of a gathering of Microsoft associates."
For a more balanced view of Mr. Ballmer, you can watch his interview with Guy Kawasaki.