Complex sentence: It was famous (infamous?) as the location of the Sunday Afternoon Wet Jockstrap Dance Contest from about 1974 to about 1992--entering this contest is how many San Francisco Go-Go dancers began their go-go dance careers.
Split into simpler sentences: It was famous as the location of the Sunday Afternoon Wet Jockstrap Dance Contest from about 1974 to about 1992. Entering this contest is how many San Francisco Go-Go dancers began their go-go dance careers.