I saw something called Cat Ears in a cycling equipment catalog, and looked them up online. Here's the web site address that I found: cat-ears.
How good are they? The testimonials that I read are favorable, but I can't know whether they'd work for me unless I get some and try them.
If I get caught in the rain, are wet cat-ears still effective? How do they stand up to sunblock?
Earplugs while riding might block out too much sound. I don't enjoy having anything stuffed into my ears, and needing earplugs to sleep (I wish I didn't need them!) is plenty enough earplug time for me. If I had to ride alongside heavy traffic, maybe an earplug only in the left ear would do. There are some LOUD sounds out there!