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.
Errbit - The open source error catcher that's Airbrake API compliant
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
SQLAlchemy - SQLAlchemy is the Python SQL toolkit and Object Relational Mapper that gives application developers the full power and flexibility of SQL.
Better Uptime - We call you when your website goes down
SqlPad - Run SQL in your browser and chart the results