As J finishes sticker sheets, I often peel the remaining border and stick it on a sheet of paper. It’s saved for some random rainy day… or days spent inside with a colicky (but adorable) baby.
I gave J some dot markers and a border sheet of what had been a set of smiley face stickers. Each empty circle was bordered with a different color. I simply asked J to use the dot markers to fill in each circle with the corresponding color. Simple, yet effective in entertaining while I fed his little brother.