41–50 of 1001 posts
Regular expressions fall into this category. While they might take longer to master, you should know the basics after an hour. I've been surprised at how often people convert long lists line-by-line. You can sometimes take what was a multiple-hour task and complete it with a handful of cryptic characters.
While you'll have to do a lot of practice to have the moves come fluidly and naturally, you can learn the basic principles of boxing or self defence very quickly if you do a 1-on-1 session with a pro.
Even for myself - someone that does 4-6 hours of boxing a week, it was incredibly valuable getting a couple of 1-on-1 sessions and having my technique scrutinised.
How a blockchain works.
Learn how to read quarterly earnings (and other financial documents). It's amazing how simply it is to see if a company is making money / losing money and how that'll impact your view of the world. For instance, Uber as it is today, is going out of or dramatically changing its business. Might not see that from all the hype, might not see it from all the user, but the terms sheet doesn't quarterly earnings doesn't lie…
Keyboard shortcuts for Excel + what exactly a Pivot Table is
Qualifies at 54 minutes!
In my opinion it is the single most important piece of computer science insight with the constraint that you only have less than an hour.
I often use binary search as a sort of thought experiment into whether something is "obvious" or not. As a child, I would say exponential growth is the one thing that I developed no intuition for between the age of 1–11. Even now, I regard exponentiation as the one really fundamental thing you possibly won't discover or have intuition for on your own and first see it at school (in contrast to addition or multiplication maybe). And even then, you have to accept exponential growth before you start to "understand" it. Maybe if you are Gauss, it's different for you...
Binary search is also a nice way of explaining counting, specifically the combinatorics thereof. You can write down the numbers [0,...,2^n-1] in binary, and then show how when you halve each time with binary search, you actually are just checking the leading bit (and then discarding it). When you have discarded all the bits in that way, then you have found the position you are looking for.