* Is the data really pulled in live from the web? With the exception of the Wikipedia articles, which I summarised in advance, yes. Everything on screen really was live data.
* Did you know who was going to appear? No — but the selection process was algorithmic, not random. It was always going to pick someone interesting. As an extra safety net, a few minutes before I went on stage someone else checked who the system had chosen: they forced a re-selection if it picked someone under 18, someone in the middle of anything stressful or traumatic, or someone who appeared likely to react badly to the phone call.
* How did you do the day-of-the-week calculation? See the annotation during the video credits. As for the speed, I was exceptionally lucky: the date was a very easy one to calculate.
* Did the person you called ever call back? Nope. But then, I did drop that disposable phone in my glass of water at the end of the talk.