Adobe Learning Manager - Adobe Learning Manager (formerly Adobe Captivate Prime LMS) is easy to setup and helps in delivering engaging learning experiences in a personalized manner across devices.
Space Engine - Space Engine is a realistic virtual Universe you can explore on your computer.
Udemy - Online Courses - Learn Anything, On Your Schedule
Celestia - Real-time 3D visualization of space
Moodle - Moodle is the world's most popular learning management system. Start creating your online learning site in minutes!
Stellarium - Stellarium is a free open source planetarium for your computer.