Another project watchers might find interesting is the top post on r/Excel, where someone made a video player in Excel because his machine was completely locked down.
My favourite (ab)use of Excel, which is already on your list, is using it for HDR photography[0].
While I'd never use it for day-to-day anything, things like this are a really interesting way to show how things like HDR photography actually work. Excel can be very approachable for stuff like this.
Another project watchers might find interesting is the top post on r/Excel, where someone made a video player in Excel because his machine was completely locked down.
https://old.reddit.com/r/excel/comments/2jtd2f/worked_on_a_c...
(Gwern has a whole list of accidentally/surprisingly turing-complete things at [2])
1. https://www.youtube.com/watch?v=uNjxe8ShM-8
2. https://www.gwern.net/Turing-complete
https://www.youtube.com/playlist?list=PLjIYRqpIFecpDSXqCOddU...
While I'd never use it for day-to-day anything, things like this are a really interesting way to show how things like HDR photography actually work. Excel can be very approachable for stuff like this.
[0] https://www.youtube.com/watch?v=bkQJdaGGVM8