Maybe I'm the last one to find/discover this trick but I was so pleased to find it, I had to share it anyways.
Often when browsing directories in Windows Explorer you want to open a command shell, using the directory being viewed as the current directory. In older versions of Windows you could add an item to the context menu by adding a registry setting or installing a third-party utility.
In Windows 7 (and possibly Vista, Windows 2008) a menu item is added to the context-sensitive right-click menu by holding down SHIFT as you click:

Yvan Rodrigues has 23 years of experience in information systems and software development for the manufacturing sector. He runs
Red Cell Innovation Inc./
L'innovation de Globules Rouges, a consulting company focusing on efficiency and automation of manufacturing and business processes for small businesses, healthcare, and the public sector.
Yvan draws on experience at
Mabel's Labels Inc. as Manager of Systems and Development, and the
University of Waterloo as Information Systems Manager.
Yvan supports open-source software. He is a committer for
SharpKit (C# to Javascript cross-compiler) and
WebIssues (Issue/Ticket Management System), and contributes to MySQL, Ghostscript, iTextSharp, Bacula, FreeBSD, MonoTouch, and Mono for Android.