Zcash

Zcash is yet another digital currency along similar lines as Bitcoin, but designed to be untraceable (Bitcoin, despite its anonymity, does preserve historic records via the blockchain which might allow others to snoop into your transactions). The 2016 release produced a frenzy of activity and skyrocketing prices (which didn't last, though the market cap has increased as more of the virtual currency has been issued).

Links

 * Official site
 * New York Times article
 * Price and activity chart