Great nugget by Darren Dreger at TSN:

Pittsburgh Penguins co-owner Mario Lemieux spent time with the coaching staff and head coach Dan Bylsma on Monday, working on the white board to illustrate some diagrams.

I asked Bylsma about it afterwards and he said it's somewhat unique and a little bit unusual, but one Penguins player also told me that Lemieux went into the dressing room after a game in Washington during that series to talk to the players about the power plays.