Ask HN: Help w/ Software Development presentation to middle schoolers

My son's school just sent a request for me to participate in the middle school 'career investigation immersion'. In the program, parents come in and give

- a brief presentation of the career - hands on activity (15-20 minutes) - Q&A (5-10 minutes)

I'm a software developer (+10 years) that has worked on web and mobile applications, with some hobby electronics experience (arduino, pi).

Any ideas on what might be interesting for a short hands-on activity for middle schoolers? I feel like I should definitely do this, but I don't really have much experience with that age group (my son is 3 1/2, so isn't part of that group).

Thanks!