I just spent the weekend rebuilding my dads PC, with my old PC internals. Its all an upgrade for him.
This man used to work for TI and helped design the Speak and Spell. He lectures me on the proper care and feeding of IC chips, silicon wafers and other things of the sort but was afraid to open a case.
Once we got it opened and I explained the layout and showed him the schematics, he had it all together, and the OS install running in 30 mins. It was a great feeling, for both of us.