In the Legion's Way district in Illium is a little obstacle course challenge called Back to Basic that requires you run into/near some markers and how fast you finish determines your reward level.
When the challenge fails and you hit the retry button the marker that was to be your next from the previous try doesn't despawn... Finishing the challenge with Bronze time is really easy, so just run through the course and when the final marker is all that is left, press the red X to fail and then press retry and simply run into the final marker for instant Gold reward and a 10x chance at your choice of reward every hour.
Location and reward specifics can be seen here.