Probably one of the coolest and stupidest things I've ever coded.
A 3k line HTML/JS code to replicate the visuals of a mobile app I was designing.
For ridiculous and useless that this project might be, it genuinely made me very good in the JavaScript overall, and tested my notions of UI design for the first time.
The full working prototype can be found here: https://shire.csci.morningside.edu/scp002/Travel&Do/Travel&Do.html