It happened during last night's game with the Phoenix Suns. After playing 796 career NBA game, Klay Thompson was ejected for the first time ever last night.
Klay got into it with Suns guard Devin Booker. After both received technical fouls, Klay continued to argue with refs. That's when he got another foul, and was ejected from the game. He didn't leave the court without yelling at the Suns bench though.