Then there was the infamous left-handed game, where Larry got bored and told his team-mates he was going to shoot left-handed:
So Celtics had won 14 of their last 15 games (most with McHale injured). Apparently Bird told his teammates he was getting bored so he decided to challenge himself by finishing EVERY shot with his left hand (ie. everything not a jumpshot). He did this till the last 6 minutes or so of the 4th period.
He ended up dropping 47/14/11 (had 35/15/11 just the night before), and 22 points came from his left hand, because he felt like doing it for whatever reason. If this isn't impressive enough, he forces overtime and then hits the game-winning shot with 3 seconds left in OT. There was a stretch in the 3rd-4th where he scored 12 straight points with his left, and at the end of regulation he had more points with his left than he did with his right.