generics-unboxing.cs

IFetchThings fetcher = new ClientFetcher();
object fetched = fetcher.Fetch(); // object is really a Client (Boxed as an object)

// let's convert the object to a client
Client c = (Client)fetched; // Unbox fetched into Client - performance hit
	// the compiler can't see any problem with this
	// and it works at run-time

// let's convert the object to a project
Project p = (project)fetched; // Unbox fetched into Project - performance hit
	// the compiler can't see a problem with this
	// but when it runs you get an InvalidCastException - Whoops