She has her favorites and we practice finding colors. Most of the buttons to her are "Byou" and then "gween" and then maybe "yeh-woah". I get to knit nearby and keep an eye on all those little buttons and she moves them from jar to the floor to her hands to a cup. For added fun I gave her two ice cube trays. 20 - 30 minutes of fairly peaceful playtime.
Lucky for me, my knits of late have not required buttons, but I've got some in my queue (for holiday knitting) that do - I should figure out the button choices now and set them aside. Buttons seem to have a way of just walking off in this house - I still haven't found those other buttons I originally bought for the PrestoChangeO sweater! And now I know about two little legs that are awfully fond of them!