For kicks, I'm going to start with a scenario that actually appears in one of the books. Though it may not have much practical application, it's a good intro into how Nancy's exceptional mind works
You're trapped inside an airplane and bound for who-knows-where. The pilot is an enemy and your hands are tied behind your back. What do you do?
Well, on one occasion, this exact thing happens to Nancy! What are the odds? Well anyway, even with your hands tied behind your back you should be able to reach for some lipstick in your pocket. Don't have lipstick? Try for a permanent marker or eyeliner (or if you're in a dramatic mood, you could cut yourself and use blood, but only use that for last resort). With your writing medium, draw an S.O.S. backwards on the window of the airplane. Chances are, your boyfriend will be flying in a plane right next to you and will see it!
That one was kind of a joke, but I would love to hear any "real-life" scenarios from people. Let me know if you have any ideas.