"That's a cute little fan. What's it for? A laptop?"
"Hmmm? Oh. That. No, it goes on a CPU heat sync for active cooling. Give me a minute and I'll show you the case fans. Go see if they have the video card you wanted while I do this."
The daughter then happily skipped off to the video card section, referencing a piece of crumpled, smudged notebook paper.
Later on I saw the two of them heading to the checkout. The daughter was giddy with glee at the pile of parts before her and her father was reminding her she'd have to wait until the weekend for them to put it together. They were going to build the computer together.