Some fun: photocopy a drawing by an older kid, and have a younger kid color it.
My son Jules (2 1/2) recently discovered drawing and he loves music like his brother, Owen (he’ll be 5 next month), so I photocopied a drawing of an orchestra Owen made back in May, and Jules went to town on the photocopies with Slick Stix, Do-A-Dots, and some other markers.
They’re my new favorite drawings.