I didn't do the research, but I'm pretty confident that this is an NHL first...
In a game between the Pittsburgh Penguins and the Ottawa Senators, brothers Pierre-Olivier and Mathieu Joseph took coincidental minor penalties for high-sticking.
Their parents happened to be in attendance for the momentous occasion - their two sons playing against each other for the first time in the NHL.
It's safe to say that their reaction was absolute gold:
There is a very short list of parents who can say that they had two sons make the NHL, but the parents of Mathieu and Pierre-Olivier are probably the only ones who watched their sons head to the box together!