We all know how some modern children will never know the relationship between a cassette, and a pencil.
Are there any quaint, older things that your children are fascinated by, such as TVs that are not flat-screen, video recorders, telephones with dials? I inherited a "transistorised record player", which I get out occasionally (still in perfect working order), I can't wait to show it to my nieces, especially the auto-change mechanism.