This video by Udacity.com is an excellent aid to understanding what UX is.
The video is presented in an animated form and breaks it down simply, allowing the viewer to understand the concept of UX clearly. It demonstrates that UX is comprised of design, accessibility, usability, system performance, marketing, and utility, rather than simply stating a vague definition.
The video also does a great job of distinguishing between UI (user interface) and UX (user experience,) using metaphors to highlight the difference and the way the two fields work together.
Moreover, it takes care to mention problems that developers face, ensuring that viewers have a multidimensional understanding of UX.