I've had a couple of good ones, although not as good as this:
V late interview to accommodate everyone's work schedule. So at 7pm, leaving building and reception staff are not there. This is the 5th interview so it's with the Super Big Cheese. He says he'll walk me out as obviously no one is around. Get in the lift, making small talk.... I realise I've picked up, and brought with me, their water glass. (realise dit because I used the hand holding it to gesture and make a point....). Technically I did get the job, but by the time it happened, neither I nor them was in a position for me to take it. It was complicated!
I'd been interviewing for my dream job. Had interview with relative big wig who had been 100% completely poker faced. Was convinced he wasn't even slightly interested in hiring me. Everything goes quiet. I have surgery to remove my gallbladder. Suddenly get call, "the whole process was paused due to internal stuff but you're the preferred candidate and big wig who saw you 3 weeks ago has now convinced everyone but you have to come see some other bigwigs who have veto powers.)
So I rush into the office, 10 days post surgery. Half way through interview, shift on my chair, make embarrassing pained squeal. I honestly remember almost nothing else from that interview - I might have been high on the pain drugs.
I got that job and worked there for years. The original big wig, it turned out, had been trying to get me and had to fight a few people. He was my biggest supporter, saw me get a number of promotions etc. I owe a lot to him even though during the interview I was absolutely convinced he loathed me!