Hello J.,
You live sounds like mine! I am involved in MOMS Club and I am also an Area Coordinator for 6 So. Orange County Chapters. Plus, my son just started preschool this past Sept and I am the President of the Boosters for the school, I run my own business, my son is involved in Tumbling Classes (which will end in 2 weeks and he will then start up Mommy and Me cooking class till the holiday break) Plus, I am working with my city to clean up a park in my neigborhood, like actually designing the park and all. So when I read your question I was thinking gosh that sounds like me!
Anyways, I just did this project with my son right after his nap today. Its the Footprint Ghosts that I saw someone else reply with. Although instead of just using a black marker for the eyes, I purchased the goggley eyes from JoAnn's. My son is using this project to send the Grandparents, Godparents and a few special friends Halloween cards. So, not only did we have fun with paint on the bottom of our feet, I also let him walk on our patio so he has his little feet print on the concrete, which can be easily hosed off. But, he will also all the stamp and some halloween stickers to the envelope.
My son is 3 and loves to put stickers (any kind) on paper, he doesn't like to color the paper just put stickers on it.
Hope this helps,
M.