If your like me at all your pretty rough on your controllers especially after playing Mario Party for hours. I put together this how to video to simply repair your Nintendo 64 controller joystick. You can get the replacement part for fairly cheap and it only takes 5 minutes to switch out the part. If you need Nintendo 64 controllers to begin with try finding them at flea marks, yard sales or thrift stores. Be patient because you can often find them for a dollar or two, especially if they have a broken joystick.
Here is a list/links to the tools and replacement parts I used in the video: