Last week, our two year old Tauren discovered Shadows. He was awestruck. Tauren loves waving at himself and once kissed his own shadow. Funny. You will be surprised by how little you really need to entertain two-year-olds.
I tried to show him some hand shadow puppets but I realised my hand puppetry needed some revision. Here are some excellent and I think, pretty easy tutorials:
This video by Mouzhan Yousefi is simple and effective.