My own list is of length 1 as a category of events. Back in July (it's a bit harder now), the odds that someone's calculated sha256 sum solved a new bitcoin blo

My own list is of length 1 as a category of events. Back in July (it's a bit harder now), the odds that someone's calculated sha256 sum solved a new bitcoin block were around 2^-68. This very tiny probability event was observed on average once every 10 minutes. 2^-80 is absurdly small. But that only means something useful if the number of attempts isn't absurdly large.