I know this sounds bad, but in hockey this happens decently often. An illegal stick is one that has too much curve on it. Goal scorers use these to get more movement on their shot.
And to underscore that it isn't a big deal, all it means it Jagr got a two minute penalty. The reason that you don't see more illegal stick calls, is because the opposing teams bench has to call for a measurement. And if the opposing team in wrong in thinking someone has an illegal stick, they get a two minute penalty for delay of game.