Expiry Shenanigans

While I decided this week not to be an idle screenwatcher if there is nothing to be done, this morning's expiry was a bit of fun.
My liabilities went out worthless. I was short 4200 puts, and with the F almost 100 above they looked pretty safe so we won't mention how I accidentally paid a fiver each on IB. Doh! What I should have been focused on was the 4300 call- which in the space of 30 minutes went from 6 to 30. I am sure there are expiry experts, and I have met a real life specialist in this arena, but I do like the wild punts based on the predictability of a rising market from the preceding thursday lunchtime, or the Fri morning swings.
I can imagine a few niche traders around the world who trade these few hours once a month, spending the rest of their time sailing or on the golf course. It's a low risk strategy with such rich risk reward.
Meanwhile I was delighted to see Pakistan beat South Africa- I'm convinced that SA are in league with the devil, they just seem to make impossible catches, and have batsmen who never get themselves out.