This website. I've had many iterations over the years, but I settled on this design and have been really happy with it for now. It was my first project using Python/Django and I used it to learn the framework and to learn testing out various security measures such as a honeypot field to prevent bots from spamming, learning how to set up HTTPS, etc. It's been a lot of fun. I've also used it as a place to write and post about things that interest me.
My current work on this site is migrating over to a Rust/Rocket implementation. Updates coming soon!