Have you ever been to one of those websites where the code you're seeing looks exactly how it would look if you were using a text editor like Sublime or Atom? That's called syntax highlighting and it would be an extremely difficult and tedious task to create from scratch. But don't fret, you don't have to do it from scratch ever since Ivan Sagalaev created Highlight.js to tackle this very task. To see a bunch of different examples (different languages with different styles) check out the website. Did I mention how easy it is to use this? You just include a few files, write a few lines of code and then it works perfectly. Go to the usage page for more information on exactly how to use Hithlight.js in your projects.
Ever have the desire to know what ping your internet is running at? Or what about your current download/upload speeds? Well Sindre Sorhus also had those same desires and he ended up creating speed-test. I know, not the most exciting name. This is a Command Line Interface (CLI) which is probably the simplest thing in the world to use. Using NPM, just install it. Then run it by typing it's name into the command line. That's it. There will be some wait time while it starts checking and a few seconds later you'll know your ping, download speed, and upload speed.
This one is just goofy, but I love it anyway. I'm honestly not sure what prompted Tim Holman to create Elevator.js, but I sure am glad he did. What this project does is when you hit the "Back to Top" button at the bottom of the page, it takes you back up to the top the same way an elevator would. I could explain, but it'd be better if yo saw it. There's an example on the website. If you want to use this in any of your projects it's actually quite simple. Just include Elevator.js in your website and then create an Elevator object with the main audio and the ending audio. The GitHub page explains exactly how to do everything. This just goes to show you that you don't have to be serious all the time to put good code out there. Having fun is a big part of coding.