People who go to see a performance or exhibition.
It's usually fun to be showgoers because you get to see something interesting or entertaining.
Examples:
The showgoers clapped and cheered at the end of the play.
The museum was full of showgoers admiring the paintings.
The showgoers sat quietly and watched the movie.
The showgoers laughed and clapped when the clown fell down.
The showgoers were so excited, they couldn't stop talking about the show.
The showgoers had a great time at the concert.