How old were your 2 under 2 LOs when they started being able to play together? Mine are currently 3.5 months and 17 months. DS (the older one) has lately started bringing his toys, wanting to show them to his sister. He also loves sitting and reading to her. She smiles at him and loves when he's paying attention to her- she watches him wherever he goes.

I know she's too young to really "play" and won't be old enough for awhile but I'm just curious about when it started for other people.