Madonna di Campiglio, Italy • Sometime around 11 p.m., pitch-black, snow falling at a fearsome rate and having just manhandled our 1964 Porsche 356 Cabriolet around what felt like the 200th hairpin of what was the third (maybe fourth) mountain pass — anticipating when, not if, the back end was going to slide out — I had an epiphany: I was having a bucket list experience and it was fantastic — provided I didn’t screw up on the next turn and pitch my co-driver and I 1,500 metres off the side of said mountain pass.

Why I was on this particularly hellish stretch of switchback is easy to explain, courtesy of an invitation by Porsche Italia to drive the 48-year-old cabriolet in the 24th Winter Marathon — a vintage rally event for front- or rear-wheel-drive cars built no later than 1968 — through Italy’s Dolomite mountain range.

Why I was doing this is more complicated. A believer and occasional victim of Murphy’s Law (anything that can go wrong will go wrong) — not to mention other related epigrams — has provided the inspiration to create my own law. Called Harper’s Rule of Infrequent Competition, it is variable — applicable for out-of-shape weekend warriors involved in team sports (don’t play worse than the worst player on your team; don’t get hurt) or occasional motorsport participation (don’t finish last; don’t break the car). The Winter Marathon was giving both Murphy’s Law and Harper’s Rule a workout.