The knee of Orion is marked by the bright star Rigel, and just off to the side is the large glowing Witch Head nebula, which really does look like a classic depiction of a hag's face: open-mouth, scraggly nose, deep eyes, gaping as she looks off to the right. 

This image was taken by astrophotographer Rogelio Andreo, and was a small piece of a vast Orion mosaic he made. It was so incredibly beautiful that I picked it as my Number 1 Astronomy picture of 2010.  

Image credit: Rogelio Andreo

Original blog post: The Top 14 Astronomy Pictures of 2010