I'm starting this page in December of 2011. I've been thinking of December as the traditional month for major miniseries events on Sci-Fi Channel (and now Syfy) for years now, so I thought I should go to the trouble of pointing this out. I think it started in 2000, with "Frank Herbert's Dune," which I'm sure I watched, though I don't have a review of it. That may be before I started writing reviews of anything, on my site. I forget. Maybe I should try to see it again someday so I can write a review. Of course, at that time, I wouldn't have thought of this December miniseries thing as a tradition. (The network occasionally airs miniseries at various other times of year, but those ones are outside the scope of this page. They're not events, and they generally don't have the same quality or prestige as the December events.)
I don't recall anything like this having happened in 2001, but in 2002, there was Steven Spielberg Presents: Taken, a 10-part, 20-hour event that for me is the epitome of the tradition. One of these days I'm going to have to get it on DVD, because it really was amazing. I feel like it might be this that made me first start thinking of December in terms of this tradition, but that might just be a retroactive memory. It seems unlikely for such a thing to have occurred to me for the second such event, especially after skipping a year in between miniseries.
In 2003, if anything could be said to fit the bill of the tradition, I suppose it would be the miniseries that launched the new Battlestar Galactica series. I don't seem to have written a review of that (or if I did, I later scaled it back and simply incorporated it into my review of the series itself). I am a bit hesitant about including it in the tradition, but it does seem to be the closest thing to qualify that year. After all, it was technically a miniseries, even if I tend to think of it more as a pilot; and of course, it did air in December on Sci-Fi. It's also a bit more likely that it was this year that I first started to notice a pattern in Sci-Fi's annual schedule... but again, I can't remember for sure.
In 2004, there was Legend of Earthsea. I don't remember it well, but I'm sure it was not especially well received. And I don't really have much interest in ever seeing it again.
In 2005, there was The Triangle, which I remember being aware of at the time, but I didn't get a chance to see it. However, I now have it on DVD, so I watched it in 2011.
In 2006, there was The Lost Room, which was fairly cool. And I would venture to say this might be what really, finally solidified my concept of "December miniseries events on Sci-Fi." (Ironically, it's also possible that concept may have been solidified for me the previous year, which was the first time I didn't manage to actually see the annual event. But I'd rather say it happened with this miniseries.) I do have it on DVD, so I'm sure I'll watch it again, someday.
In 2007, there was Tin Man. Regardless of when the concept first occurred to me or when I first noticed a pattern or when I became convinced that there really was a pattern, it was with this miniseries that I absolutely, positively could not be shaken in my assumption that a major event would happen on SFC every December, and that more often than not, it'd be really cool. Way cooler than any other original movie or miniseries event you would see at any other time of year, on SFC. (In fact, almost everything else throughout the year is just cheapo redonkulous junk they use to make a quick profit from people who dig schlocky movies; I usually don't even bother with such things, as I'd just end up wanting my time back.) Tin Man also started the sub-tradition of these miniseries events being modern takes on classic fantasy stories (this one a very original take on "The Wizard of Oz"). I should get it on DVD someday.
In 2008, it seems there was nothing (aside from a rerun of "Tin Man"). So much for my unbreakable pattern. Sigh.
In 2009, there was Alice, a modern take on "Alice in Wonderland." Happy to see the pattern resume, even if the miniseries wasn't quite as good as I might've hoped. Still, I should get it on DVD someday, maybe. Oh yeah, and incidentally, it was in July of this year that Sci-Fi Channel changed its name to "Syfy," a move which was considered a good idea by pretty much no one. (But of course, that has nothing to do with this miniseries.)
In 2010... again nothing? I mean, except reruns of "Tin Man" and "Alice." (And a rerun of "Riverworld," which first aired in April, though I've never seen it.) So like, what's up wit dat, Syfy?
In 2011, there was Neverland, a sort of prequel to "Peter Pan." Since I didn't have Syfy when it aired, I watched it on DVD in 2012.
I'm pretty sure there was nothing in 2012 or 2013. I still don't have Syfy, but nevertheless I find its recent lack of December miniseries events disturbing.
In 2014, there was Ascension, which was originally supposed to be a limited series starting in late November. Because it was rescheduled, I reckon it counts as a December miniseries event.
In 2015, there was Childhood's End, though I'm not sure when I'll get to see that.
I'm pretty sure there was nothing in 2016-18.