Go to the ExCo Fair, held at the beginning of each semester. You can sign up for the classes you want to take, as well as ask the instructors any questions you have about a class. Most classes select their students by random lottery, although some have an application. If you're accepted into an ExCo, you can register on PRESTO (just like your other classes). (If you're not an Oberlin College student, you don't need to register at all.)
students
How do I change the variable credit hours for my ExCo?
You can change your variable hours with the Variable Credit option in PRESTO. Alternately, you can go to the Registrar's Office and fill out a Schedule Adjustment Request form (they're gray).
How do Variable Credit Hours work with ExCo classes?
All ExCos can be taken for credit up to the maximum number the course is approved for, and any class may be taken for zero credits. So a one-credit class may be taken for one credit or for zero credits. This way, students are not restricted from taking an ExCo because of semester credit limits.