Battledome, Rec Room, Hover Junkers
There's a bunch more, but these are the most polished, in my opinion. Battledome/Rec Room really shine because you can get right next to a person, wave at them, talk to them (built in mic on the Vive headset). It's super immersive and cool to be literally right next to a person that is maybe in another country.
It still seems like early days for multiplayer. There's no way to see other people's facial expressions, and the avatars are pretty basic. There's also no support for having a local multiplayer experience. Hololens is doing some interesting things, allowing multiple headsets to see the same holograms, but their hardware is still super limited. The void is also doing interesting things.
I guess I should have said that I want better multiplayer.
The Void's Ghostbusters game looks amazing. They are using custom hardware and a more expensive tracking technique, but it is an awesome example of a "VR-Arcade" sort of business.
Disclosure: A friend of mine worked on it.