I am planning to give a presentation/demonstration on regular expressions at work to encourage young developers to add this powerful and important tool in their toolbox.
Just teaching syntax doesn't cut it. I often see people say nice. After the presentation, they get on with their programming lives without ever thinking of using it mostly.
I am raking my grey matter to come up with some solid examples, not just problems that matches 'cat' and 'cut'. I missed to note down the occasions of my regex enlightenments to use here. :^(
Do you have some inspiring problems to share that could be solved with regex?
Update: Wow! I didn't expect so many wonderful answers. Thank you. For now, I will mark @tdammers' answer as accepted. Bring those regex memories keep coming :-)