Given that you have only 5 to 15 minutes, I think you have to decide whether you would rather a) give an overview of the field, which is now overwhelmingly huge or b) give a specific usable case study<p>I'd go with b), the specific, usable example. I teach R and basic machine learning (and/or how one would use either with trading strategies, etc; depends on the person's interests) over Skype + TeamViewer and what I find is that doing something together on the command line is most engaging. For example, "Here's a CSV of super market sales and clearly, column 4, amount spent by the customer, seems to be predictable based on the time of the day. Let's see a couple of ways we can figure out how!", and dive in. (I use randomForest and talk about variable importance and classification vs. regression. The fact that they can now actually use this ML technique right away on real data, thanks to the robustness of randomForest, is exciting!<p>These are one-on-one sessions that I am referring to, but I suspect it would scale equally well to a 1:30 classroom situation, too.