Easy (if you’re level 60 or so) Argent Dawn Tabard.
Check out the WoW Insider today.
Basically, head down to the Dark Portal, get a quest from the Argent Dawn, to kill, or be involved in the killing of, 6 Invading Felguards. Took the wife and I five minutes to do it and we each got an Argent Dawn Tabard for service, “heroic” at that!, fighting the invasion at the Dark Portal.
Basically the tabard adds a little fun in that you can “use” it and you’ll /flex, without the emote, and an arcane explosion (harmless) blows up around you. Fun. And it’s an Argent Dawn Tabard without having to reach Exalted (or whatever) with them.
I suppose you’ll have some fun watching Warlock Felguards in the mix, and if you’re on a PvP server, heh, enjoy that too. I’d say this will be a pretty busy place for a bit.