There is nothing you can do with and arduino that you cannot do with dedicated elecrtonic components!
Its just that your citcuit to do something will fill a house and the Arduino a cigarette packet.
As an example i was working on the plans for a solar panel rotator and ended up running out of room drawing the schematics on an A3 page only to find that an arduino and a motor driver could do it all and add data logging for current, amps and daylight hours.
Ahh another project that is still on the drawing board.
For nostalgia you could try a project including nixie tubes just to show the kids that YOUR tech is not outdated yet.
I know if my grandfather was still around i would have made him an antenna rotator position system displaying the degrees in nixie tubes.
Daz