Say what?

On my looooooooooooooong drive to work today (I had to drop Muffin off to be groomed, so I got to drive in during rush hour, which almost turned me into a screaming, road rage-aholic mess), I heard a commercial on the radio for a ballet performance happening next week here in Nashville. Apparently, the Nashville Ballet is presenting “Rite of Spring” at the Tennessee Performing Arts Center (TPAC for those of you who live in Nashvegas). Anyway, the commercial included this phrase: This ballet is for mature audiences. Say again?

My question: Exactly what kind of ballet is this?