NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
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.
Zohno Z-Term - The Easy-to-Use Active Directory User Termination Tool
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Server Density - Trusted monitoring built by experts.
Better Uptime - We call you when your website goes down