I passed a rider on a steep hill yesterday, who was repairing his chain for the third time, on the same hill. I was prepared to stop if he needed assistance, but I probably would not get going again during to the severity of the hill, but he was happy enough and could manage so I laboured onwards and upwards. Why it had snapped three times I do not know, possibly a bad repair job for two of the breakages.
I remember the good old days before multi tools, when all you carried was a small 1" nail and a small nut, if your chain snapped, you looked around for a heavy stone etc to use as a hammer, lay the chain over the nut, and carefully tap the pin out, or almost out, depending on the repair.
The hill in question for those on "Season of the Mists", it was the one after the second checkpoint at the activity center.