Webmin - Webmin is a web-based interface for system administration for Unix.
cPanel - With its first-class support and rich feature set, cPanel & WHM has been the web hosting industry's most reliable, intuitive control panel since 1997.
ClearOS - A very good alternative for Windows Server, for free
Google App Engine - A powerful platform to build web and mobile apps that scale automatically.
Salesforce Platform - Salesforce Platform is a comprehensive PaaS solution that paves the way for the developers to test, build, and mitigate the issues in the cloud application before the final deployment.
ServerPilot.io - Centralized hosting control panel for Wordpress and PHP web sites