World Bog Snorkelling Championship

Two lengths of a 60-yard trench cut through a freezing Welsh peat bog, zero visibility, flippers mandatory, any stroke that isn't front or back crawl disqualified. That's the entire World Bog Snorkelling Championship, run every August Bank Holiday since 1985 in Llanwrtyd Wells — Britain's smallest town, population in the low hundreds, which somehow still manages to organize one of the most sincerely bizarre sporting events in the country.

The event is real, it's timed, and people train for it, which makes it funnier rather than less so. You will not see the water in front of you. You will not know your position. You will finish caked in a substance that doesn't fully wash out of anything, and you will be handed a certificate for your trouble.

This is trivially easy to do solo — entering is an individual event by default, registration runs through green-events.co.uk for about £15, and the "Bog Bus" shuttle from the town square handles the logistics you'd otherwise worry about. Llanwrtyd Wells is small enough that everyone attending ends up mingling regardless of who they arrived with. Book lodging early: rooms in a town this size sell out fast for its one weekend of global relevance.