FakeMenu
Sample program to demonstrate how a program can display a popup window which does not deactivate its parent. This can be used for things like a magnifying glass window or a pseudo-menu.
SendTo
Demonstrates how an application can display a menu that lists all of the user's "Send To" extensions and send a file to the extension the user selects.

This last item has zip-all to do with Raymond Chen. Its a sample that was shipped with early SDK's and Microsofts censors have decided to pull it. Its the windows 3.1 pseudo source for DefWindowProc and DefDlgProc, and while its rather dated I personally think its still rather important for the clues it gives.

DefProc
The windows 3.1 pseudo source code for DefWindowProc, and DefDlgProc.