My friend Peter and I often use Remote Assistance to collaborate on projects. He and I were doing some things today in Visual Studio, and while I was watching, a beautiful window appeared that showed the open files and windows and such, complete with appropriate icons. "Whoa!", I said, "What was that?!" "What", he replied, "this?" The window re-appeared. Turns out, it was the Ctrl-Tab window. For some reason, I never even thought of using it to browse the open windows. I always assumed I had to navigate the frightful tabbed interface, which just might actually be usable with that little trick.
I felt better when I typed in a type name and Intellisense didn't recongnize it. A quick right-click->Resolve instantly added the appropriate using statement. Peter hadn't seen that feature. Although I guess Ctrl-Tab's been a standard for much longer than Resolve.