Play time IS a big deal, and here's an interesting article from NPR and another from babycenter that explain why.
I try to make sure that Erik and Paisley get some time to themselves every day to just spend how they want. Granted, Paisley is pretty restricted by what she's able to do right now, but even she can sit and play with her fingers and toes, practice making faces, and learn that she's able to function when not held or attended to by someone else. Erik loves to play on his own. He will voluntarily go down the hall to his bedroom to play by himself for pretty long stretches of time (long for a 13 month old anyways). He loves to sit and look at his books while I am doing other things around the house. He's even invented his own little games that he loves to play whenever he can. It's so fun to watch these two do their thing when they think no one is looking.