Cooper's Hill Cheese Rolling
Brockworth, United Kingdom · May 31 · Main quest length: 1 day
Here is the entire event: a 8lb wheel of Double Gloucester gets released at the top of a hill with a 1-in-2 gradient, and a crowd of strangers throws themselves down after it. Nobody wins the cheese, really — you're chasing a rolling wheel of dairy down a slope steep enough that "running" stops being the applicable verb somewhere around the second bounce. People leave on stretchers most years. People come back most years anyway.
Say this plainly, because the event itself won't: Cooper's Hill has had no official organizer since 2010, when local authorities pulled the plug over insurance liability. It runs anyway — self-organized, no entry fee, no barriers, no medical tent with your name on a clipboard, just a hillside near Gloucester that a few thousand people decide to show up to every Spring Bank Holiday Monday regardless of what's sanctioned. That's not a loophole, it's the whole ethos. You are attending an event that exists because enough people refused to let bureaucracy cancel it, and you should treat the total absence of official safety infrastructure as the load-bearing fact it is.
Solo works fine here because nobody's event to begin with — the "crowd" is a fence-line of spectators and a rotating cast of racers who mostly don't know each other either. Watch from the fence if you have any self-preservation instinct, or don't, and join a heat; either way you're one more person on a hill that belongs to everyone and no one.