Hilarious thread. Love it. I am one that never takes myself too seriously.
I've had some good ones over the years of my cycling:
-First time on clipless pedals, high school, Look ATB pedals, and I didn't know what the hell this tension adjustment is. Well the pedals come from the factory nearly fully tensioned. Got out, clipped in. Rode around the driveway... came to a stop aaaand slowly fell over. When I tried to unclip on the ground, the pedals were so tight, the cleat turned on the bottom of the shoe. I ended up having to unlace the shoes. My old man thought all this was pretty hysterical.
-Once on our annual mtb trip to Killington, VT, we came to a stop on a trail to wait for slower riders. I have a habit of not unclipping when a tree is handy to lean on. I put my arm out, while looking at my buddy, trying to be all smooth. Well, my hand missed the tree by a good foot and over I went.
-In that same vein I remember a time coming to a stop on a trail when the tree I selected to hang on to was a little too young to suppor my weight. Over I went with the tree. Upon hitting the ground, the tree catapulted my bike back up and over. That was a proud moment.
-When I was younger (middle school?) I was riding around on my slick new Huffy. I low flying (and I mean low, probably less than 1,000 feet) C-130 heading into Westover flew right over my house. I looked up to see it, lost my balance, feel over and spraigned my wrist.
-Later in high school, the very first ride of our newly formed mountain bike club, it was raining but I was so eager to show off my mad skillz to my friends. We weren't even at the trailhead and I watched my buddy hop a big white pine root and tweak his bars. I attempted to do the same thing but managed to aim right for another tree upon landing. It was that day I found out what exactly tacoing a wheel was.
-And possibly the dumbest... backed into my garage with my bike on my roof rack. This was after not five minutes before exiting my car to get my mail at the end of my driveway and thinking "better remember not to back into my garage today!" Amazingly no damage to the bike or the rack. $1000 worth of damage to my roof. Brilliant.
I have others, I'm sure I'll think of them.