A guy named Alfred di Blasi gave a demonstration on cable TV of the Apple Lisa, one of the first commercially available WIMP computer systems*, back in 1984. He's digitised the original video and put it on YouTube.
There's quite a long introduction about the history of the video, but the main content starts around five minutes in.
It's truly amazing to think how far we've come. It's also incredible to see how functional the Lisa was, back when 99.99% of users were playing with DOS command lines! I love how he has to explain all the things we take for granted these days.
Of course, the Lisa's entry price was $US3500 (and those are 1984 dollars!), so it's unsurprising that it never really took off.
* We all know that the Lisa was effectively a rip-off of the Xerox Star, which was released three years earlier, but I've never seen a video showing it off, so you'll have to be content with this Lisa one.