I recall Turus uncovered a few strange sparkling events in Netherstorm. I ran across one event briefly on my warrior, but it disappeared as soon as I noticed something was amiss. However, I recently ran into one such event that spawned while I was finishing a quest on my druid:
Look at the combat log. It appears that random parts of Netherstorm will be afflicted by an arcane vortex, allowing you to regenerate mana. Pretty neat!