Finite state automata (FSAs) sound complicated, but the basic idea is as simple as drawing a map.
This fun activity is based around a fictitious pirate story which leads to the unlikely topic of reasoning about patterns in sequences of characters
The binary number system plays a central role in how information of all kinds is stored on computers. Understanding binary can lift a lot of the mystery from computers, because at a fundamental level they're really just machines for flipping binary digits on and off.