While renowned for popularising the incorporation of analogue joysticks into modern video game controllers, the Nintendo 64 Controller's joystick is, in fact, its biggest flaw. Those who played their N64 extensively back in its heyday will remember that the stick would become loose after extended use, so much so that it would eventually become unusable.
If you've left your N64 in the past, then this probably doesn't matter. But it's becoming increasingly difficult (and expensive) for today's dedicated community of N64 fans to source controllers which still have decent, working joysticks.
This is where ENKKO's crowdfunding project to provide quality joystick repair parts for the N64 controller comes in to save the day. The campaign has already attracted over $6,000 of pledges on Kickstarter, and it's not hard to see why; unlike many of the third-party joystick replacement units already available on the market, ENKKO's solution will be reversed-engineered to get as close to the OEM stick as possible.
Understandably, something so novel and bespoke isn't cheap to produce. The purpose of ENKKO's Kickstarter campaign is to raise money to get the materials needed to take the project further: primarily an aluminium mould to accurately mass-produce the sticks.
If you still play your N64 on a regular basis and want to live in a world where high-quality joysticks for the controller are plentiful, then take a look at the ENKKO Kickstarter project page and donate some money. According to a timeline on the page, ENKKO currently hopes to start delivering rewards in May.