I'm surprised War Thunder isn't on the list. Has native Rift support already built in, multiple views to choose from (pilot's eyes, virtual cockpit, etc), and is ridiculously immersive.
It's one of the main demos all my friends flip out about, and has them talking about for days after coming to my place and playing it.
I put it in as an honourable mention. It's a spectacular demo, but the actual gameplay I've found is pretty hard to get into, not helped by the "it's online so you're terrified of the League of Legends effect" problem.
It's one of the main demos all my friends flip out about, and has them talking about for days after coming to my place and playing it.