I donated for the first time Thursday and passed out... too thin and hadn't eaten much that day, so it was a bad idea. It was my first time though so I wasn't too embarassed... just gotta wait for my metabolism to slow down and my weight to go up. :p
For what it's worth on the gay thing, they had a questionaire beforehand and one of them was "if you are male, have you ever had sex with another man?" (paraphrasing, but I remember the word "ever" because a lot of the questions were time specific... such as 1977+, 1988(?)+). They did have separate questions for AIDS and being a gay male though, which is sad... unless there's another STD I don't know about that they're at higher risk for? I dunno. It was with
Bonfils.
Also if you lie on any questions and the blood test reveals that, they report you to the federal government (at least in US and ban you from donating any organs/tissues/etc. afterwards).