The 11:30 Mass at our parish this past Sunday was probably one of the only Masses in the country which used only the Introit to open the liturgy, and it was unintentional.
The introit was supposed to be chanted before the entrance hymn, but the celebrating priest was apparently not aware of that, and so he began processing up the aisle. Everyone stood, the introit with verse was just long enough to get him up to his chair, and after that, there wasn't any point in delaying things with a hymn, so the Mass proceeded. It was actually rather elegant, if you didn't know that it was unplanned.
3 hours ago