As you know, I've been trying to find easy things to entertain Emma with stuff I have on hand around the house. I saw this idea over at Life of a Modern Mom and figured we'd give it a shot. I simply printed a picture of Emma's choosing out and taped it to the window. I then placed a blank piece over top and showed her how to trace the picture.
It worked for a little bit, but I got busy with something else and she got impatient following the lines. We ended up having a mass of scribbles with a hint of a picture underneath.
We'll have to try this again later when she's a little older, but for a quick activity it was perfect!