In the 70's, disaster flicks were huge business, and Universal Studios was eager-beaver to take it to the next level. This next level was called "Sensurround", and it was used for a handful of movies including 1974's Earthquake and 1976's Midway.
You know how you get a funny feeling if you hold a subwoofer up to your belly and crank the tunes? This was the basic idea behind Sensurround. They equipped theaters with giant speakers that would rumble out the bass at certain points in the movie, so that moviegoers would actually feel their insides quivering due to the sonic attack.
The funny thing was, Sensurround was somewhat of a hit, and helped to make these films legitimate event tickets. Unfortunately, there were a few hitches with the system: it caused several patrons to become physically sick, it damaged the actual theater it was in (cracks were quickly seen on the walls and ceilings, and one theater saw a huge chunk of roof come down and flatten 10 empty seats), and people sitting in the next theater over couldn't hear their own movie. This, coupled with the cost of the equipment, saw the early end of Sensurround.
I can only imagine if these were still in operation in today's extreme sports culture - who wouldn't want to go to a movie where you could potentially get a nose bleed or hit by a ceiling tile for just showing up?