Yehudit Brachah of Jewschool eloquently posts about Jewish cultural immersion at the Matisyahu concert in Boston last nite and her interactions with Pseudo Jew. Keep in mind, no acid was involved. Or none that we know of. 

Me: So you said you're in Jerusalem, huh? What street do you live on? [I am really asking in a nice tone, I promise. I am giving him a chance.
Pseudo-Jew: Uh… [cough] the fourth street. From the center.
Me: Really. What bus line are you on? What neighborhood do you live in? [I was really trying to give him a chance. A chance to back down? A chance to admit his ploy? I'm not sure. But I didn't expect him to keep going.]
Pseudo-Jew: Umm… well, actually, my neighborhood just got bombed. So I had to move.
Me: No, no it didn't.
Pseudo-Jew: No, really. It did. But I used to live in [cough at same time as saying:] Jachmnbadah.
Me: Huh.

Me: Where did you get your kippah?
Pseudo-Jew: Huh? My what?
Me: [taking the kippah off his head… yes, I was being somewhat obnoxious at this point, but he was also touching my waist now and leaning in to answer me] Don't touch me. What's this on your head?
Pseudo-Jew: The yamakah?
Me: Where did you get it?
Pseudo-Jew: "Where did I get it? I bought it! In Peabody. Do you know Peabody, Mass? Where are you from?
Me: Yeah, I know Peabody. I'm from here. And Jerusalem. I lived there last year.
Pseudo-Jew: Oh really?
Me: Yeah. You should really learn the neighborhoods of Jerusalem before pretending to live there. [I promise I said it sweetly.]
Pseudo-Jew: Well, I've only been there for two months, so I don't really know.
Me: Well, good luck finding your way. Good night.