If you want to add more spy/cyberpunk-esque gadgets to your life, Sgnl has you covered. A "smart strap", it replaces the current strap on your watch and allows you to answer calls by placing your fingertip on your ear and speaking through the microphone on the strap. It's also said to allow for outbound calls. To put it another way, it's a much cooler take on the "traditional" Bluetooth headset.
Sgnl -- created by Samsung spin-off Innomdle Lab -- is discrete in that audio is directed into your ear directly through bodily vibrations, and noise canceling capabilities means you'll be able to hear whoever's on the other end clearly.
It's not hard to imagine a smartwatch company will design a product with this functionality built in before long, especially if Sgnl takes off (and it may very well, with $834,308 raised on Kickstarter in about a week, far above its $50,000 ask). If you don't want to wait, $99 will get you the tech before long.