EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.
Communifire - Enterprise Social Collaboration Software
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
LS Intranet - LS Intranet is a corporate intranet that facilitates multiple employees collaborating on projects, and working in synergy.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Unily - Unily is a cloud-based intranet solution designed by SharePoint consultancy BrightStarr.