I'll wear my OOo shirt and baseball cap too! :-)
Then again, I always wear a sweater and a jacket, so it won't be so visible :-)
But you can still see the baseball cap!
Keep the t-shirt clean for the conference! ;-)
There should be a phone rental service, where you get to have a cell phone for a
week or something.
I'm sure I've seen them at some airports in the USA, but at absurd prices. My theory is that you can rent *anything* in the USA if you know where to look.