This story accompanies Head of the Class.
Taking a page from Donald Rumsfeld and his various options to determine who knows what and when, we've put together a brief list of some incidents and items many Gen Yers -- typically designated as those born between 1977 and 1994 -- may be unaware of.
* Inserting a VHS tape into a VCR to record something
* 8-track cartridges
* Watching TV on a network's schedule
* Not knowing who is calling you on the phone
* Polaroid instant cameras
* Changing the TV channel without a remote
* A time before Super Bowls, AIDS or cable news channels
* The sound of a modem connecting
* Dot-matrix printers
* Mainframe computer terminals
* Print encyclopedias
* Banks before ATMs
* When spam was a meat product (or Monty Python sketch)
* Rotary-dial telephones
* TV before "reality TV"
Source for much of the list is a July 22, 2009 Geek Dad column by Nathan Barry on Wired.com.