Formal:
* What classes do you have? This is the most direct and common translation.
* What are your classes? This is a slightly more formal option.
Informal:
* What classes are you taking? This is a more casual way to ask.
* What classes do you take? This is another informal option.
You could also use:
* What subjects are you studying? This is a broader question that encompasses more than just classes.
* What are your classes like? This asks for more information about the nature of the classes.
The best translation depends on your relationship with the person you are talking to and the overall context of the conversation.