I've done some really stupid things on bicycles.
I've tried a wheelie on a bike which had no nuts holding on the front wheel. It hurt.
I've gone helter-skeltering down a long steep hill on a bike with no brakes. It hurt, a lot.
I've tried to ride a bike home from a party, drunk out of my skull, projectile vomiting cider. It hurt the next day, and they didn't press charges.
So, this latest revelation will come as no surprise to you in the slightest.
When I tell you that our obsession of the week was medieval knights, you will probably be able to skip to the final part of this tale knowing full well the agonies involved. But then you'd miss the bit about the all-girl wrestling.
So, the noble brotherhood of knights, it was then. Or, in reality, suits of armour made out of bits of wood wrapped in all the tinfoil we could find, meaning the following Sunday's roast would be burned to a crisp. Helmets were plastic buckets rendered useless with the addition of eye-holes. And our swords were the old standby - bastard great lumps of wood with a pointy bit on the end.
I was to be Sir Scary of Twyford, and by God I looked the part. The part being that of a twat wearing a dustbin.
And there stood Sir John, the Black Knight. Black, on account of the black bucket he had on his head, and carrying the biggest, scariest sword ever, which had begun life as part of a scaffolding he dug up in his garden.
The two armies came together with a whiny teenage roar, and we spent several, bruising minutes beating the seven bells out of each other. Oh, what fun, and hardly any of us went home crying to their mum with a nosebleed. Unfortunately, it was the school arsehole, Peter (pronounced with your tongue pressed firmly against your lower lip), whose mum was huge, frightening and rumoured to have had killed a man just to see him die, and would hammer any person who harmed a hair on her darling boy's head into the ground with one big, hairy fist.
And here she came, all milling arms, cigarette smoke, and a voice like a foghorn, trailing her blood-stained, tin-foil encrusted berk of a son behind.
"WHICH ONE OF YOU BASTARDS CRIPPLED MY PETER?" she boomed. That's Peter: pronounced with your tongue pressed firmly against your lower lip, of course.
We legged it to the park, and hid in the bushes until she went home for her hormone injection.
And there, we made a discovery.
"Hey look! Lances!"
They weren't lances, simply rather long staves of wood that had probably been part of the old scout hut at some stage. But, by God, they would do for these Knights of the Wonky Table.
Indeed, there would be a joust.
God knows why I did it. I still don't know to this day. I knew it would hurt. In fact, I knew it would be agony, yet I still did it.
Goaded on by my seconds, I mounted my bike and faced off against my good friend, the evil Sir John, still the Black Knight.
Lacking a maiden to drop her hanky or anything (do you think any girl with a brain in her head would be interested in our bunch of stupids?), someone shouted "GO!" and we cycled like fury at each other, lances resting on our handlebars.
Closer and closer we got, cycling as hard as we could despite the extra weight and inconvenience of our "armour" and the fact that I couldn't actually see anything what with the bucket on my head twisting round so the eye holes were round the back somewhere.
And then: there was a sickening crunch, which turned out to be me. Or, a large bit of wood catching me square in the chest. This was followed by another sickening crunch, which was also Sir Scary - this time hitting the deck as my steed disappeared from under me. Everything went black.
Then, everything went white, white, white. Someone had pulled the bucket from my head to see if I were dead or not. Adjusting to the light, and no longer seeing double, Sir John stood over me, sword in hand, ready to deliver the coup de grace.
"No John," said a voice, "You're not meant to really kill him."
I was dragged to my feet. My makeshift breast plate was cleaved clean in two, and instead of looking a vanquished knight, fallen on the field of honour, I looked like a tramp.
"Say something, Scary," said John.
"I feel sick."
And I was.
Eventually, I found my way home. There, in the middle of my chest, right next to my sister's claw-marks, was a large, square bruise. It would be my badge of honour.