How Do Curved Classes Usually Work?

I’ve never been in a curved class before. How does the grading usually work? Is it something roughly along the lines of (these are baseless guesstimates!):

85% percentile and above: A
67% percentile and above: B
50% percentile and above: C
33% percentile and above: D
0% percentile and above: F

It depends entirely on how the class is curved. I know some professors who decide on the curve at the end of the class, taking into account the natural distinctions in averages. I know others who will curve to a particular average (so, they will curve everybody’s grade such that the average is XX).

Yeah, it totally depends on the department and professor. In my old department classes were curved so that there was a certain percentage of As and Bs in each class, so grades were scaled accordingly.