gistfile1.cs

public class Course
{
  private readonly List<Registrant> registrants = new List<Registrant>();

  public CourseTemplate Template { get; private set; }
  public bool IsMorning { get; private set; }
  public IEnumerable<Registrant> Registrants { get { return registrants; } }
  public bool IsFull { get { return Template.Limit < registrants.Count; } }
  public bool IsEmpty { get { return registrants.Count == 0; } }

  public Course(CourseTemplate template, bool isMorning)
  {
    IsMorning = isMorning;
    Template = template;
  }

  public void Register(Registrant registrant)
  {
    if (!registrants.Contains(registrant))
      registrants.Add(registrant);
  }

  public void Start()
  {
    // ... allocate instructor and run the course ...
  }

  public void AwardDiplomas()
  {
    // ... award diplomas to all registrants who passed
  }

  public override bool Equals(object obj)
  {
    var other = obj as Course;
    if (other == null)
      return false;
    return Equals(registrants, other.registrants) && Equals(Template, other.Template) && IsMorning.Equals(other.IsMorning);
  }

// some hashcode implementation ....
}