public class Room
{
    public string Name { get; set; }
    public bool Bookable { get; set; }

    public Room(string name, bool bookable);
}

Room r = new Room ("101", true);

public enum BookingStatus
{
    Bookable,
    NotBookable
}

public class Room
{
    public string Name { get; set; }
    public BookingStatus Bookable { get; set; }

    public Room(string name, BookingStatus bookable);
}

Room r = new Room ("101", BookingStatus.Bookable);

public abstract class Room
{
     public string Name { get; set; }

     public abstract bool Bookable { get; }
}

public class BookableRoom : Room
{
    public override bool Bookable
    {
        get { return true; }
    }
}

public class NonBookableRoom : Room
{
    public override bool Bookable
    {
        get { return false; }
    }
}