Ubuntu is a fork of the Debian project's codebase. The original aim of the Ubuntu developers was to create an easy-to-use Linux desktop, which has led to a large user base as well as helping people new to Linux switch over. On a side note Windows users can install Ubuntu right in Windows, Ubuntu will install into Windows as an application that will give users access to all the great and Open Source Software that only runs on Linux without having to leave Windows.
Mark Shuttleworth Keynote from Ubuntu Developers Summit. Mark covers topics such as Steam coming to Linux, Ubuntu desktop for Android and What to expect on the server side.
Get Ubuntu: http://www.ubuntu.com/
Learn and Get Help With and Ubuntu: https://help.ubuntu.com/community
Develop for Ubuntu: http://developer.ubuntu.com/