I have just spent the past two weeks updating all the timelines on the SuperWiki!
(oddly, LJ isn't letting me left-click the link - if you want to follow the link, do a right click "open in new tab/window" and it should work. Hopefully it's just giving me trouble and it's working fine for you guys.)
The wiki only had Preseries, S1-S2, and the Mythology Timeline before - and most of those were inaccurate to the point where I couldn't look at them without becoming enraged. So, I got permission to create new pages and change the wrong things and now EVERYTHING IS GLORIOUS (and accurate).
Actually, in the process of updating the SuperWiki, I realized that I could actually figure out a few dates that I had marked down as "Unknown" before! So, temporarily, the SuperWiki timelines are now MORE accurate than the versions that I have on this LJ. That'll change in the next few days, though, as I update things over here to match.
The SuperWiki's Mythology Timeline still only goes up until the end of S5, but I am TIRED, guys... so updating it past then will have to wait for another time... or possibly someone else to do it. In the meantime, if you want to figure out when a particular event in the myth-arc takes place, you can just go to the timeline for the appropriate season. I also left the table that the SuperWiki had for the pre-series timeline, because I liked the way it colour-coded certain information, and I just added events that were missing... though, not all of them, because I learned that editing tables on Wikis is really really annoying, so I just did what I thought were the necessary additions.