It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of oscillator, ...

As a father of three I don't get out for "me time" very often, and certainly not classes to broaden my geeky horizons. But the Mrs. graciously allowed me to take a class, so I signed up for a course ...