Question

Is there an example login page via a pop-up window?
Also, if the user performs some operation on the site that requires authentication, then show the login screen (if user not authorized).

Answer 1

You should just create you Login view, as you would implement it usually. And then apply fancybox (http://fancybox.net/) or bootstrap-modal(http://twitter.github.com/bootstrap/javascript.html) to make it work as modal.

Regarding re-direction: as soon as you use [Authorize] attribute as controller attribute and not-authorized user tries to hit its action, he will be redirected automatically;