I am enjoying reading through these topical threads, so thought I'd start one of my own.
I was recently reading about "Ear Stelae" from ancient Egypt. The true meaning of the ears is still unclear, but most speculation suggests that it's so the gods could hear your prayers when making offerings. I have posted a picture of an example below. As I was working through my Hungarian stamp collection I came across a stamp to commemorate the 11th International Audiology Congress in Budapest in 1972 (SC 2185), also pictured below. It got me thinking - What other "Ear Stamps" are out there?