Shimano XTR: Synchronized Shift
"Shimano's new XTR Di2 M9050 family features the optional Shimano Synchronized Shift, allowing for customizable synchronized front and rear shifting via a single FIREBOLT shifter. By simplifying the rider interface, shifting a mountain bike will have never felt so natural."
While I'm a bit skeptical of taking a bike whose shifting is wireless and relies on a battery, the idea of programmable shifts of both derailleurs from one shifter is pretty damn cool. Then again, I wonder how it feels. It's common to take power off the pedals just as a shift happens, and if the system is determining when to shift either end, I wonder how you'll know when to do that.
Still, neat.