It really came down to the simply interaction of my son, 3 and my daughter, 1. The usual interaction follows something like this. "Stop sitting on her head.... No, don't clothesline her...., you can't 'sweep' her face with the broom, no!... Don't drop your metal dump truck on her head.... Your sister is not a bed, stop lying on top of her.... So on and so forth.
But, this morning, my son calmly walks into the office, picks out a book and announces he's going to read it to his sister. And he did!
I may be young still, but I'm wise enough to know this is hardly ever the case. Such a pronouncement from my son is usually code for, "I took some medical tape from the bathroom and I'm going to use this book as a bodyboard to practice my EMT skills on my sister." A few minutes later, said sister is screaming and by the time I arrive on the scene it's something akin to Dr. Frankenstein's laboratory complete with maniacal laughter (my son providing the laughter, of course).
But today, wonder of wonders, he sat down on the couch and proceeded to read to his sister. And today, wonder of wonders, his sister complied. For she is not so innocent herself; but I would digress to head down that path.
As I finish this post, I'm sure I just violated a time-tested unspoken rule amongst parents to never publicly acknowledge such wondrous behavior lest the parenting gods curse us with bed-wetting-WWE-imitating children that... wait, gotta go, the screaming has begun already.