This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Yes, loosely speaking, anti-pattern is something that is routinely done in a wrong manner. For example beginners learning struts or php coders coming into Rails frequently write scriptlets because they seem more powerful/easy for their tasks.
Thus, anti-patterns are opposite of design patterns when it comes to applicability. DPs provide a guidemap for development/learning whereas anti-DPs educate us on common pitfalls in development.
As rails packs with itself a lot of stuff under the hood, like MVC, ORM & RESTful architecture, we frequently find ourselves having a poor or non-eloquent design. Here's when books like these help you out.