Cycling one; Was doing what was meant to be largely canal-towpath based route from Northampton down to London, (part of a longer tour) but this day's leg was to take me off-route to meet a friend in St Albans and stay over for the night. Glorious day, riding was going really well, met other cyclists, pub lunch and a nice chat, etc, carried on and somehow I LOST THE CANAL just south of Leighton Buzzard... I have no idea how I lost it, but I did. I ended up pushing my heavily-laden tourer along an increasingly inaccessible river bank.
Then the heavens opened.... really opened, thunder, lightning, peeing down rain. 'The map' was on my phone... that got wet and stopped working. Left the river, rode up a few lanes, got totally lost, nobody around to ask. Found a road pointing me towards Aylesbury, and I though OK, I know my way from there, but it's a main road... the A41. So, I cycled the A41 from (near) Aylesbury to Hemel Hemptstead in torrential rain... busy dual carriageway, spray leaping from lorries and cars whizzing past inches away at full pelt... I could not have been wetter, to be honest.... and the rain didn't stop till I got to St Albans.... but at least my waterproof panniers lived up to their toughest ever test.