Getting the company to sit me down next to one of their teams for a couple of hours. Just see what they're doing. How work is managed, how code reviews are being done.
You want to hire me, not the other way around. But good luck in explaining this when you have to write a doubly linked list in pure C because some guy on a conference said that every dev needs to be able to do that.

It was called a hackathon, but was probably more a CTF on a distributed TOR network. Organized by Dutch tax police (FIOD) for students. Finished it single-handledly in 18 hours, in front of several teams consisting of 6 people. Immediately got a job offer, but declined since I still wanted to do a master's :)

Basically an IMDb clone that reads my IMDb watchlist. I can add counts to it though (i.e. I watched a movie 10 times). Every day it runs runs the changes of that day through the OMDb API and then shows the amount of time I could've spent not watching movies on a dashboard.

Currently I've spent almost 10% of my life watching movies and series. Dear lord. Why did I make this.

In PHP, strings are classes, functions, whatever you them to be. I feel so filthy, I need a shower after typing this.