I was at a 57th birthday bash last night, and the birthday boy asked me to perform for some of his friends. Things were going nicely and I was asked to finish with my expanded version of Brown's Perfect Coin Prediction. Basically, people select a coin from their loose change (not just a 10p), and I go down the line telling them the mint years. It gets a nice, eerie reaction and some bizarre thories that I'm only too happy to let the specs explore

Well, I went through the intro patter about coins picking up personalities throughout their lives and how it might just be possible to detect things about them, such as their mint years. But when I asked the group to note the years, they all started blinking and trying to hold their choices up to the light, at arms length, etc. It turned out that no one, not one single person, had brought their reading glasses!
Luckily, I hadn't used my ID, so I changed tack and finished on an impossible prediction. But boy oh boy, did I learn a lesson!