The “obscure foreign phrase” thing is kind of a cliche, but it’s definitely a solid standby, so I’m surprised nobody’s mentioned it by now.
Time was, you could get by knowing a few phrases in a single language – French, say – but our increasingly global culture makes it necessary to jumble up the tongues for maximum effect. Wankers Without Borders, don’tcha know.
A few ones to get you started (note, only one phrase from a given language is represented):
Schadenfreude (SHAW-d’n-Froy-duh). A classic, discussed recently in a couple of threads here. It’s a German word that means “taking pleasure in the misfortune of others.” Example: chuckling at the fake-ID bust of the Bush daughter, and at her dad’s discomfort. German words that have become passe – i.e., mainstream, and therefore not pretentious enough – include “zeitgeist” and “gestalt.”
Cum grano salis (koom GRAH-no SAH-lis). Latin for “with a grain of salt.” I’m sure you can come up with appropriate usages.
Mise en scéne (meez ahn sayn). A term invented by French cinema critics to describe, essentially, “what the movie screen looks like.” It encompasses the scenery, the color scheme, the framing, and so on. For particular filmmakers, the term actually does have value, but most of the time it’s overkill, like a Porsche engine in a golf cart. For the truly pretentious, you can expand the usage into new territories, as long as you’re vague about it – the “mise en scéne” of the Catholic sex scandal, for example, which also creates interesting McLuhanesque echoes. (Don’t know McLuhan? Add him to your list of people whose theories you must know, if only to mock.)
And speaking of McLuhan, you should have at your disposal a variety of historical figures the average person doesn’t know about, names you can drop in for comparisons: “Yes, but aren’t you simply repeating the mistakes of Chiang Kai-Shek?” or, if you want to be really snarky, “Cheney is the Mrs. Wilson to George’s Woodrow.”
Welcome to pretentious-ville! It’s kind of fun, but it’s not a lot of laughs – not out loud laughs, anyway. (I’m a sometime resident, as I suddenly realized a couple of days ago at the Seattle International Film Festival when I actually thought about the fact that I was watching a slow, black-and-white Russian film and making mental notes about comparing it to the work of Jim Jarmusch for my eventual written review. Pretentious, indeed.)