It seems I sufferred something called ‘transient global amnesia’ last Saturday, when I lost my memory of the previous two days for several hours.
After seeing the doctor I decided to look it up and one of the links on the first google results page was to the ‘Mayo Clinic’, where one of the professors is a chap we met on Sanibel Island earlier this year. His card is the only one on my desk and it sits under my monitor (but for no specific reason).