Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
GitHub Visualizer - Enter user/repo and see the project visually
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Widgetic - An App Store for every platform.
Better Uptime - We call you when your website goes down
Little Star - Efficiently and easily manage your GitHub stars