node.js

Brian Peiris demonstrates RiftSketch, a web app where you write JavaScript with Three.js while wearing an Oculus Rift and watch the world around you change live. It runs on Firefox builds with WebVR.

Bruce Hauman live-codes Flappy Bird in ClojureScript in about six minutes, using figwheel to hot-reload changes into the running game. The demo shows game behavior being changed interactively without restarting.

A five-minute video showing how to build a counter in the Imba web programming language in under a minute, then style it.

David Heinemeier Hansson builds a blog engine with Ruby on Rails in 15 minutes, the demo that launched Rails' momentum.

The Michigan TypeScript group shows the Doom engine running entirely inside the TypeScript type system. It is open source, and two follow-up videos cover why and how they did it.

The original 2012 screencast introducing Meteor, a JavaScript framework for building web apps quickly. It demonstrates realtime updates, latency compensation and low boilerplate.

A demo excerpt from a 2016 Bay Area Rust meetup showing Servo's WebRender drawing CSS on the GPU at very high frame rates. It presents the promise of GPU-based browser rendering.