At the Steam Dev Days event Valve demoed a new prototype controller for the HTC Vive.
Information on the new controller is thin on the ground, as the event is only for developers and not press.
The only real information that we have to go on is that players can seemingly open and close their hand without dropping the controller, which if true would make it much easier to make realistic interactions with objecting in the VR world.
The controller also appears to be slightly smaller than the current Vive controllers and seemingly have some different input devices.
The controller is currently a prototype and is being shown to developers to get their opinions and feedback, so chances are more information about how the controllers work will start to appear over the next few days.
Valve has also used the Steam Dev Days event to announce that Steam now has over 10,000 games, that the Steam Link will be built into some upcoming Samsung TVs and that Dualshock support is officially coming to Steam.