I feel a little bit ashamed to post this but whatever. I used to write bots for a popular online game that would harvest materials and sell stuff in the games auction house. At first I only wanted to automate some tedious, boring tasks in the game, but over time I got really good at it to the point where I wouldnt have to touch my guy for days. Anyway, there where lots of bots on my servers and we would all undercut each other to a point where our materials where worth almost nothing. Around this time the company released an API where you could pull auction house data for your server. I wrote some scripts that would pull the data, store them in redis and crunch some numbers that I would later feed to my bots, to gain some advantage. Basically, I was able to withhold my stock when the price reached a certain threshold and buyout all of my competitions stock at super low prices. By that time I had already "scaled up" and ran several instances on various servers, all full automated by some python scripts. I wrote a web socket based web interface that allowed me to see my bots log messages in real time from work. I set up alerts when game masters messaged so I was able to answer them to prove that I was not a bot, all remotely. It was so much fun. At the end of each month I would sell the in-game currency to some chinese companies, the last few months I made between 300-500 € / month, double that amount around christmas. One day, the bann hammer (rightfully so!) hit me hard and I lost all my accounts. It still was a fun experience that introduced me to several new technologies.