So I was reading a blog entry from Scott Gu which has a nice piece of code for crating a new validation object in MVC3

Where “logically” is the best place to store this in a MVC3 environment? Is it best to store it in a new project linked to the solution? Is there a app_code equivalent folder in MVC as there is in Webforms?
I like to keep everything neat and tidy when coding (possible OCD!) but want to pick best practises amongst the community.
I figure code like this could be reused in a variety of projects, and isn’t specific to the web application that I’m working on. So I create a special utilities project, and inside that project I may have a namespace for Annotations or Validation or something like that where I’d put a class like this.