Let's get this party started with Lionheart's question...
What is that barred off instance looking portal thing in Stormwind, by Old Town? Were the gates once open?
There are actually two of these in Stormwind. Neither of them were ever open, they're relics of unfinished projects. One is a closed off little guarded island in the Canals. That one was going to be the Stormwind Vault, probably a dungeon like Arcatraz or the upcoming Violet Hold in Dalaran. Probably.
There's also the barred off one at the end of the Canals, right down the way from that one. This is probably the one you're referring to, I'm going to guess? I don't think we've gotten a real answer on this was supposed to be, but it was probably going to be the portal to player housing. They actually did start work on player housing at one point, but never got far. There are relics of it in the game files. Half completed houses/structures, things like that. They all use the Stormwind motif for their appearance, and they would have to put it somewhere. Through this portal is a safe bet.
Jaina Proudmoore and Arthas. Any chance they'll hook up against in the future? What are the details of their history together?
...get back together? Good gosh I hope not. That's be messed up! I guess nothing is impossible, but I sincerely doubt this.
As for their history, it's not a very long or involved one. Essentially, Jaina is the daughter of Admiral Daelin Proudmoore, who was buddies with King Terenas of Lordaeron. Arthas was the Prince of Lordaeron. Jaina also wiggled her way into an apprenticeship under Archmage Antonidas, ruler of Dalaran. So the two of them we the shining stars of their kingdoms, and being in that sort of position just sort of led them to eachother.
Think of it as a Hollywood relationship. Two huge stars, common household names. Attractive, popular, probably pretty cool people. They're definitely going to hook up given the opportunity. And again like Hollywood relationships, everyone in the world knew about their fling pretty much immediately, or as fast as word travels. Their friends bugged them about it, their parents probably immediately tried to talk them into marrying eachother for political and social reasons, all eyes were on them. That sucks! So nothing major really came out of it. They had feelings for eachother, but they ultimately went and did their own thing. Having everyone watching your relationship really makes the whole thing hard.
Sean Riley asked...
Sports! RAAAR! Are orcs good at them? What SPORTS are played in Azeroth? What do the various races do to play SPORTS! (RARR!)
Do you count the arena as a sport? If so, there's that! Especially in Orcish culture. Beyond that, we don't really know. We can assume kids (and some adults) play some sports or games, because kids are kids and they'll always come up with something, and Leatherworkers can craft Heavy Leather Balls. I assume that the first person to make one of these made them to play a game, not not just to toss around waiting for their raid to start.
I sincerely doubt Azeroth has anything like sports leagues outside of what the Goblins pay people for, like the Arena. Competitive sports for entertainment is good for morale during war, but not when said war is on the brink of engulfing your entire world. People fit to play sports competitively are probably on the various fronts and battlefields.
I was going to embed the Sports! clip from Tim and Eric Awesome Show, Great Job! here to counter your Powerthirst reference, but I somehow feel it would be inappropriate.
I don't "get" how there can be Forsaken Death Knights. Surely a Forsaken DK is just a human or high elf (or blood elf now of course) DK, overall, right?
They're more rotten. It's easier to accept something that still resembles what they should be. A guy with cold, pale skin walking up to me would be freaky, but tolerable if I was told he's super cool. If a guy missing hunks of flesh and his jaw walked up to me, I would probably vomit on my shoes.
Plus, in the case of the Death Knights we'll be playing in Wrath, a Forsaken Death Knight very well could have been a member of the Forsaken before (s)he became a Death Knight. The Death Knights of Acherus are mostly people who were cut down by the Scourge in the Plaguelands. A Forsaken could easily get gibbed, be pulled back into the fold of the Scourge, and then be released -again- under the proper circumstances.
I remember the Panderans in Warcraft 3. I know they have their own place in Azeroth named Pandaria. Where is this place? I also know they have a hiding place in Stonetalon Mountains. Where is that, too?
Pandaren are largely a joke. Samwise Didier's nickname is 'Panda' and his alter ego reflects that. For fun, he started including them as easter eggs in the Warcraft games. There was a strong, positive fan reaction because Warcraft fans are nuts, so Chris Metzen wrote them into Warcraft. Again, a light hearted and silly thing. So do they exist in lore? Yeah, I guess they do. Will we ever know where Pandaria is, or their other settlements? No, probably not.
They use a line like "nobody has ever seen Pandaria but the Pandarens" when describing it. It's a pretty good "out." They don't need to show it to you and they probably don't want to, either. It's a nod to the fans. I don't think we'll see them in WoW, I don't think we'll ever know the location of Pandaria, but we'll see a few of them as easter eggs in Warcraft 4 or whatever.