Probably caused by static electricity. Solution: don't wear nylon (or silk) undies.
'Sir, please,' she said ... 'Will you not share your wisdom with us?'
'I have no wisdom,' he told her.
'Your experiences, then?'
'They have been trivial, uninteresting, and full of error.'
Ian M. Banks - Feersum Endjinn
It Ought to be Easy | Greasemonkey scripts