Every year,
But the "meeting" seemed much more like a rock concert, with screaming fans, blaring music, long lines and ultimately, tears.
First, 13,000 Microsoft employees headed to Key Arena in Seattle where the farewell took place. Software engineer Bob Ulrich snapped a picture:

The line to get into Key Arena to see Steve Ballmer's final Microsoft meeting.
Here's what the arena looked like as Microsoft employees poured in (via Geekwire).
Music blared including Michael Jackson's "Wanna Be Startin' Somethin'" which Ballmer played at the first annual meeting he held 30 years ago.
"The ceiling can't hold us." Ballmer at Microsoft company meeting pic.twitter.com/pnCnX6d01s
- Tom Warren (@tomwarren) September 26, 2013
"He then proceeded to jump and dance around the stage screaming at the top of his voice 'the sound of Microsoft!'" The Verge reports. Ballmer then told Microsoft employees they work for "the greatest company in the world."
The meeting ended with Bill Medley and Jennifer Warnes' "I've had The Time of My Life."
By the end, Ballmer reportedly had tears streaming down his face. He screamed along with his send out song, "I've had the time of my life!" and Microsoft employees screamed back, "We love you!"