4DX is an interesting concept:
4DX allows a motion picture presentation to be augmented with environmental effects, such as motion, odours and humidity, outside the standard video and audio.
However, I do hope that it doesn’t take off like 3D. I’m sure no one wants to watch Slumdog Millionaire in 4D, peanut butter & chocolate or not.
Iron Man 3 to Debut as a 4DX Film in Japan | News & Opinion | PCMag.com.