To create an interactive publicity stunt in preparation for the release of Gravity on BlueRay and DVD, Warner Home Entertainment allowed people to watch the movie in a very meta way: surrounded by zero gravity.
The team put together a tank filled with a certain amount of salt and ensured the temperature stayed at a regular heat comparable with how the body normally feels. This way, people laying in the tank couldn't feel the water on their body, giving them a zero gravity effect. A TV was placed at the top of the tank, so all users had to do was just sit back and enjoy the ride.
Warner Home Entertainment managed to bring a meta film experience to users with this publicity stunt.