What is the most complex and most useless thing you've programmed?

Trying to build my first OOP programs entirely on one file. Built a whole freaking calculator with it.

I wrote the code to find primes. I thought of ways to speed it up so I can find primes between large ranges of numbers. I was about 16 then and didn't know much about standard algorithms and internet was a luxury. I finally ended up with a pretty good algorithm and working code. Later, after a few years, I came to know that it has already been a popular algorithm, known to the world as Sieve of Eratosthenes.

Well our college has an erp system, meaning we could see our whole attendance along with other important stuff like calendar , notices, assignments etc up there.
The erp's ui was extremely ugly and lagged on my very poor spec Micromax phn.
So i tried to make my own way of tracking my attendance . And made an offline manually maintained subject wise attendance tracker.

Its a terrible thing. The steps to get attendance fom online are simply these :
- write the url,
- enter name password,
- click an ugly 'hamburger menu' icon,
- click attendance
-Select start date , enddate and then press enter

But In offline mode, its
-Add subject names on first launch
-Mark your attendance whenever you attend or miss the lecture
And see attendance percentage of all your subjects as well as total

Its easier to use, but has a lot of tasks to remember: add the subjects, regularly mark attendance
So overall a flop idea
(But i learned a lot)

Used machine learning (char-rnn) to come up with a name for my project. I generated 8000 new names based on legit female names, and cross-checked them with domain availability using a script I wrote. Then, out of the remaining 3000, I chose my favourites and bought them 😛

It came up with names like Chrissabelle, Patlie, Frodine, etc.

My wedding

CyberChecks and I am not even ready yet @xalys