This was a once-in-a-lifetime encounter that I wish I could repeat. Alas, I'm left with just the hilarous memories.
I was walking through a park, taking photos of some flowers with my fisheye when this squirrel ran up to my camera (hoping for some peanuts, I'm sure). I bent down to say hello and started snapping his picture. He became so curious looking into the lens (and seeing the opening and closing of the aperture/shutter) that he put his little paw on the lens and peered inside. Truly hilarious!