[solotronics]

Maybe I'm old school but I think it would be neat to bring an old rotary phone and pull out your cellphone and explain how modern phones would be magic to someone 50 years ago!

edit: this is probably boring and would not be age appropriate

[dehrmann → solotronics]

The way area codes of major cities (e.g. 212) are compressed is really clever, but sadly, I don't see it impressing fifth graders.