Inspired by a post on the blog Wait but Why, this is a website that fills out a table representing every week "in your life" (up to a user-configurable life expectancy) where the filled in cells represent the weeks already passed, and the empty cells those yet to come.
This was one of my first-ever completed web projects, and I'm pleasantly surprised that it isn't completely terrible. There are of course plenty of things I would do differently now, but overall it more or less holds up.
What I'm not pleasantly surprised about is how many more boxes are filled in now than were when I first built this in 2016.