I made a thing (Atari 2600/7800 joystick)...

 A fellow retro gaming enthusiast that I follow on Twitter posted up a 3D print of a C64 joystick. It also would work for Atari 2600 and 7800, but it's all dependent on how it's wired. 

I raided an old, worked Atari 7800 controller for the wiring and the connector, the actual joystick came from an old Ion iCade cabinet, and the buttons from an old Xbox 360 joystick that I had. I printed the 4 way gate for the controller. I followed some schematics online to get all the wires connected to the right pins on the connector, including some resistors that I ordered to have it work with the Atari 7800. The print of the joystick itself took a few hours to complete (2 different parts).

This joystick was several months in the making simply because...I don't know why. I was going back and forth (like I always do on things) whether or not to start ordering parts for it. It was supposed to be made with whatever spare parts that I had, and the thing that was holding me back was ordering new buttons for it. But, I went through a cleaning fit and found my box with a bunch of joysticks, including an old Xbox 360 joystick. Since I had all the main parts ready, I just needed a couple of resistors to finish it up. 

Prior to getting the component that I needed to finish it all up, I spend an evening getting spade connectors crimped and routed through the narrow areas, including on getting all the ground connections. Tonight, after finally getting the component I needed, I finished up the soldering for the buttons and finally got around to testing it.

...Pictures taken moments before disaster. Prior to me taking this pic, I did some initial testing with my Atari 2600 playing Joust (the only game I had nearby...I have more) and it worked fine. Both buttons worked as button pushes on the 2600, the joystick controls were pretty decent. I then brought out my 5200 to play with. I bought a board that allows you to use a 2600, 7800, SMS, and a 3 button Genesis controller. I tried several games that I had and they all worked great. Then I took this pic with Dig Dug

...oh boy...

The buttons didn't work properly, but the controls did. I used a 2600 controller I had to test and it works fine. I'm thinking that I may need a different value on the resistors that I got...or I can just use the Genesis 3 button joystick that I found in that box of joysticks...among other things...

Well, it's nice to repurpose stuff. I may attempt to make another one in the future, using all the parts in that 360 joystick.