Examples: Speak up, I'm all ears. (Some examples.)
Origins: Literal sense of the ears as instruments of hearing and eagerness to listen (source).
- listening with both ears
- eardrums are piqued
- ears are tuned
- that hush is for you
- you can’t speak too low for me!
Discussion: Originally, I went much wider in rewriting these but found I was taking the idiom beyond its original meaning. There is plenty of opportunity to rewrite using ears or hearing or speaking as extended metaphors and staying true to the heart of its idea.