Microsoft has made it's .NET 2.0 Framework beta 1 available. It's available here. In addition, you can get the SDK here.
In addition, you can also get Visual Studio 2005 here.
Microsoft seems to be targetting students with these betas.
In 2017, with the release of Delphi 10.2 Tokyo, Embarcadero introduced a specialized implementation of the Observer pattern into the System.Classes unit. While it has been in the wild for 9 years, it remains a "hidden" architecture for many, primarily because it serves as the invisible engine behind LiveBindings. Other than live bindings, you can also use the Observer pattern as a way to update component settings to the Windows registry, an .ini file, or persist it elsewhere.
System.Classes