Orphan's Week will always be a special seasonal event for me, because it was directly because of the Hail To The King, Baby) sub-achievement that I met and joined my first guild, Celtic Siege.
Up until Orphan's Week 2009, I was a solo player. I had only grouped or guilded with a handful of real-life friends, all of whom had stopped playing. So I was in a guild of one, just quietly questing, doing some PVP, still enjoying the game but finding it a bit empty. I had been level 80 for about two weeks, didn't know what DPS was, what a rotation was, what a Hit Cap was, etc. I wasn't really a huntard (reading BRK ensured that) but I just had no idea what these things were for, and had no one to ask.
In a bizarre twist of fate, I'm probably the only player who was more apprehensive about Hail To The King, Baby than School of Hard Knocks*. I kept doing /who while in Howling Fjord, looking at the many, many 80's online who were undoubtedly coming to do the achievement, but couldn't muster up the guts to just interject and ask to tag along. Finally, on the very last day of the event, I saw someone in chat looking for 1 more DPS for Utgarde Pinnacle...and I had to try it. (Dammit, I wanted that Proto-Drake!)
*Good luck on Hard Knocks, btw. Lots of great guides out there, all I can say is a) don't just waltz in and expect to get it without effort - take a few minutes and learn some battleground/PVP basics; b) go with friends who will help you get them; c) for the Alterac Valley one, skip the nearest bunkers and go straight for the farthest ones. Pray.
I was terrified of messing up and wiping the group, and was totally paranoid about not committing the group sins I'd read about, such as leaving growl on, attacking untouched mobs, or breaking CC (LOL CC. Yeah right.) I worried for nothing though. The four Celtic Siege people were friendly and cheerful, and it was a great, fun run.
I totally jumped when I walked into Svala's room and saw the giant Lich King standing there. (click for fullsize)
I also took a moment to capture our army of orphans.
The run was flawless (it was only regular UP), we all got our Orphan's Week achievements, and most importantly, after we were finished I asked for and received an invitation to the guild! (click for fullsize)
I'm still a member of Celtic Siege as Mardak (Rades is in a different weekly raiding guild) and am SUPER glad I bit the bullet and grouped with Krius, Battleground, Cerdeath and Shizukagozen a year ago. Countless guild heroic runs, help & advice tinkering with DPS/specs, and just friendly, cheerful people has made the last year incredibly awesome.
And I owe it all to Orphan's Week.