I'm currently planning a new class at my school on prototyping with arduino (which could later morph into more pcb design). I'm stuck on my first hands on lesson. I want the students to see the capabilities of the arduino, but not do anything too complex because I'd hate to fry anything on day 1.
I considered the standard "blink an LED" hello world program, but that wouldn't take up an entire class period. I have an hour and a half, and all the students are using computers that have the IDE set up so I don't need to leave time for setup.
So, what would be a good first lesson? I haven't chosen a board yet, so please specify which board and why you've chosen that one. Wiring diagrams are welcome!