Here are some other random examples of assertions that you can make (see the documentation for the full list):

var vm = new SomeViewModel();
_controller.WithModelErrors().WithCallTo(c => c.Index(vm))
    .ShouldRenderDefaultView()
    .WithModel(vm);

_controller.WithCallTo(c => c.Index())
    .ShouldRenderDefaultView()
    .WithModel<ModelType>()
    .AndModelErrorFor(m => m.Property1).ThatEquals("The error message.")
    .AndModelErrorFor(m => m.Property2);

_controller.WithCallTo(c => c.Index())
    .ShouldRenderView("ViewName");

_controller.WithCallTo(c => c.Index())
    .ShouldReturnEmptyResult();

_controller.WithCallTo(c => c.Index())
    .ShouldRedirectTo("http://www.google.com.au/");

_controller.WithCallTo(c => c.ActionWithRedirectToAction())
    .ShouldRedirectTo(c => c.ActionInSameController);

_controller.WithCallTo(c => c.Index())
    .ShouldRedirectTo<SomeOtherController>(c => c.SomeAction());

_controller.WithCallTo(c => c.Index())
    .ShouldRenderAnyFile("content/type");

_controller.WithCallTo(c => c.Index())
    .ShouldRenderFileContents("text");

_controller.WithCallTo(c => c.Index())
    .ShouldReturnContent("expected content");

_controller.WithCallTo(c => c.Index())
    .ShouldGiveHttpStatus(404);

_controller.WithCallTo(c => c.Index()).ShouldReturnJson(data =>
{
    Assert.That(data.SomeProperty, Is.EqualTo("SomeValue");
});

A real-world example can be seen in the AndTakeUserToASuccessPage method of the SuccessfulTeamResetPasswordScenario code snippet shown in one of Rob's blog posts.