Design Patterns
"If you restrict "design patterns" to GoF design patterns, some languages do provide support, you just have to look at the right lanugages. There was a discussion on this going around about a month ago, John Wiseman aggregated the links. When you think about it, C# actually implements a lot of design patterns for you, they're just generally too low level to conciously acknowlege. Aren't concepts like "scope" and "polymorphism" design patterns?"
I wouldn't categorize "scope" or "polymorphism" as design patterns (never seen them called such things). Scope is a required in any programming language and polymorphism is required in any real OO language, so they are givens. You are right about C# (or rather the BCL) implementing some design patterns for you (such as collections, etc.), but these are also givens in any modern language. If you think about it, although design patterns are, as a whole, are a lot more prominent in the minds of developers today than when the original C++ STL specs came out, language support does not seem to have made a proportional jump. Yes, you have collections of all sorts, which are very useful, but are still very primitive. There are also some interfaces in the framework (such as IServiceProvider) which are intended to promote the use of certain patterns, as well as recurring patterns within the framework itself. However, languages haven't advanced all that much since the C++ STL and templates were introduced. In fact, you could argue that we took a step back when the Framework team decided not to support generics in the 1.0 release.