I thought that if there was one online friend guaranteed to appreciate this as much as I do, it would be a Vallikat who dressed as a kitty for Halloween.
Look at teh cuteness!!

The ears work using an external neurosensor, which looks a bit like a mic for your brain. The sensor rests somewhat conspicuously on your forehead, then detects your brainwaves via electrical impulses, and possibly also voodoo. There are two basic emotions that the ears respond to; they perk up when the user is excited and droop when they're relaxed. If the wearer is particularly excited or especially relaxed, the ears wiggle. This partly reflects the ways cats' ears move based on their mood, and partly is just adorable. Or weird, depending on your perspective.