Not really sure what you want to do.
If you used a library class - a module for example - its automatically instantiated, when you use 'include
'
If you just have a generic class, and you included it somewhere, then you already have the class object loaded and can call methods on it. Or you just create an instance manually with 'object = new MyClass
'.
And then call whatever you like on 'object
'.
Whatever Information you collect inside the controller method, you can access in the view, when you place an '@'-Symbol before your variable.
So if you want your show.html.erb look like this:
<h1>My String:</h1>
<%= @mystring %>
then you have to do something like this in your controller:
def show
...
@mystring = MyClass.get_my_cool_string
...
end
Hope that helps...