For something that fits the 'my project' role, I may, and often have, just reinvented other wheels, mostly cgi, such as shopping carts, discussion forums, implementing OpenSSL for credit card transactions, session management.

I generally take a completely naive approach and am not embarrassed to 'roll my own' to see how it comes out. More often than not, comparing what I ended up with to other's solutions is extremely humbling... ;(

Some network monitoring tools got created to monitor a linux box on our home network (used for IP aliasing), mostly to watch the kid's browsing habits (which helped...), automated some site-watchers to message me or my wife of changes on sites we have personal interests in, almost anything can become a project for me.

Other times I'll just do something simply to have used something from CPAN that intrigued me.

Unless I have an actual need for a project to fill, simple triviality often gets things going. Some major things have come about while doing these types of projects.

The plus is that a great deal of my Perl education has come from these things.