Hevy - Simple workout logging, insightful analytics, and a growing community of gym athletes.
ExpressJS - Sinatra inspired web development framework for node.js -- insanely fast, flexible, and simple
HeroSnatch - User-friendly workout tracker for CrossFit athletes
Backbone.js - Give your JS App some Backbone with Models, Views, Collections, and Events
Strong.app - Strenght training logger.
FeathersJS - Wow your users. Build incredible real-time applications in record time.