Here's one of the more recent stints I had. This one was mainly because a friend of a co-developer had conflicting schedules and asked me to be a substitute. Made in 30 mins, the slides weren't as catchy as I usually make them. Plus I didn't know I was talking to freshmen - zero programming exposure. I felt like I was speaking alien to them.
To make it more awesome, I'm primarily a front-end JS developer, use Python for our backend, and we favor Go over Node.js because of some scaling stuff. It was so ironic to present Node.js when you only use it for tooling.