Microsoft's history is filled with stories about its rough culture, from it's "stack-ranking" employee reviews to how Bill Gates used to yell, "That's the stupidest thing I've ever heard.

Here's another one: Six-foot-two Steve Ballmer sometimes brings a baseball bat with him into meetings. And that's if he's feeling happy, says ex-Microsoft executive Joachim Kempin in an interview with ReadWriteWeb's Dan Lyons.

"If he’s having a really good day he’s swinging a baseball bat. Do you think that sends a signal? Sometimes he brings it with him into the conference room," Kempin said.

Ballmer isn't always so Robert-De-Niro-as-Al-Capone-in-the-Untouchables (remember that scene with the baseball bat?). He's also known to bounce a basketball through the halls, Kempin says.

This isn't the first time we've heard tales of Ballmer's explosions. He famously threw a chair across the room in 2004 and shouted the f-bomb repeatedly when Google CEO Eric Schmidt poached a key engineer.

Then there's that story of how he damaged his vocal cords so bad he neeced surgery by furiously shouting ''Windows! Windows!'' at a sales meeting in Japan.

Or the famous sweaty MonkeyBoy video (and its equally famous iPod mashup parody video)?

It's all due to Ballmer's abundance of "nervous energy," Kempin says. "He’s not a bad guy. He just goes overboard sometimes."

Worth noting, Kempin left Microsoft, and Ballmer's daily company, back in 2002, although he has been back to visit the CEO since then, he says.