Oh, well, that's Aion's new bonus experience weekends! According to community manager Tamat, Aion is introducing these brand new experience gaining opportunities to help smooth the leveling curve between levels one and 35. As long as you log on during one of these weekends and are between those levels, everything you do will garner you double experience. Crafting? Yep. Gathering? Yep. Killing? Yep, it's all there.
Now Tamat does go on to say that this is a temporary measure before they do something more permanent about the leveling curve, but it's a good start to address what is an issue to many people. Especially when, as we've said before, only 2% of the entire population is between the levels of 46-50 and Aion's endgame doesn't function well without people. Hard to PvP with no one there.