Here's an idea: a #NoJS challenge.
Making a website? Avoid using JavaScript.
See how much of the functionality and design you were planning can be done using plain HTML, CSS and other web technologies that are now embedded in the typical browser without needing JavaScript code to do any of it.
Even if it seems impossible, look it up. It just might be possible.
There's so much stuff in there now, even a seasoned webmaster could be surprised.