As you've seen on Sidebar 4.3, the every keyword is an extremely powerful tool for obtaining a list of items. You can use the Finder to get every file of the folder "Applications", or use TextEdit to get the name of every document. No matter how you use it, the every keyword is a huge timesaver.
Moreover, when you use the every keyword, you're guaranteed to get a list as the result. That makes every a perfect companion to use with the choose from list command; the combination of these two commands lets you obtain a list and then present the list onscreen.
Seeing a list of all your running programs is enormously helpful, because it lets you check what invisible programs are working in the background—and, in some cases, hogging your computer's processing power. You could, of course, use the Activity Monitor program (stored in your Applications → Utilities folder) for this task. But you could also do it with AppleScript, and that's a lot more fun and educational.
To write such a script, you have to command Mac OS X's hidden System Events program, which monitors all the other programs running on with your Mac. Proceed like this:
In Script Editor, open System Events's dictionary (File → Open Dictionary, or Shift--O).
Page Sidebar 3.4 explains the magic behind AppleScript dictionaries.
Click the Processes Suite flippy ...