If you're going to BlizzCon, you don't have to wait for Echoes of Doom to come out to get a head start on racking up achievements, at least according to the playful commentary going on in the forums right now. Here's a taste of some of the humorous achievements they've suggested you can earn at BlizzCon.
I Have No Use for This - Try to sell a piece of junk to any vendor at BlizzCon
Ruler of BlizzCon - Survived both days of BlizzCon without sleeping, eating, and showering (Blue poster Bashiok begs you not to attempt this one)
Savior of the Public - Brought enough soap for yourself and at least 1 other person (takes achievement away from Ruler of BlizzCon)
I put on pants for this! - Worry about the fact that you're missing a raid with your guild
Defender of the Throne - Order a greasy, overpriced hamburger from the convention center floor and spend at least 2 hours on the john
Everyone's Best Friend - Buy a round of drinks for the Blues
The Not-So Magic Kingdom - Go to Disneyland in Warcraft apparel
I Want My Mommy - Utter the phrase "Don't tase me Bro!" as security comes for you
THEY GOT THE KEYS MAN - Intoxicate a Blizzard CM
Munchhausen - Complain about your class to Kalgan
Nerf THIS! -Yell and nerdrage at a dev during the class panel
Oops! I Did it Again! - Come to the convention dressed as a character not pertaining to WoW
Slayer of the Dragon - Hand out mints to five people with the "dragon" breath
Okay, now it's YOUR turn! Surely we can come up with even funnier ideas for BlizzCon achievements!
[Thanks, Andrew Anderson!]