Dude, where's my interview?

So I have a job interview tomorrow - my second since coming back from travelling 6 weeks ago. I should be getting ready for it, but frankly it was hoisted on me by one of those infernal recruitment agencies. And not one of the good ones, either, but one of the ones that comes out with things like "Well, you're right that the job description is clearly asking for a high school dropout and includes the phrase 'ideally, someone with no ambition whatsoever', but they are flexible. You should go along, and see if you like it and with luck they can change the role to encompass your 7 years' experience in research and desire for people management". So I feel bad about being difficult and agree to go along. And at the interview, I basically come across as the equivalent of a grown man trying to get on the swings in the play area at the park - it's embarassing for me, embarassing for them and none of us know why I'm there.
Oh, and the worst part? The frickin agency woman hasn't even told me where the interview is or who with. I mean, this company has 4 large buildings, each with its own reception, and I haven't a clue which one I'm supposed to be going to.

So yeah, I'm feeling really positive about this one...