Two:
I ran into the back of a Plymouth Horizon in front of the White House while attending an American Chemical Society meeting in DC sometime in the 90s. This was back when the was still traffic on Pennsylvania. I was gawking and didn’t see the car in front of me. I left a thigh sized dent in the hatch. I muttered something like “Sorry,” and quickly rode away.
The second one was on a bike ride I used to lead that I called “Urban Dirt” for the Denver Bicycle Touring Club. I usually lead these in the early spring in town because there’s too much snow higher up. This one was in March and was along Cherry Creek. It’s a lot more challenging than most people thing. Not because the ride is steep or rock but it is in the trees. There was one tricky bit where you had to quickly lean out over a undercut bank of the creek so that your handlebars will clear a tree that leaned towards the creek. As soon as your handlebar cleared the tree, you had to lean back away from the creek to keep the line. I’d done the trail many times without issue.
This particular time, I leaned away from the tree and back like always but my timing was off just a tiny bit. My handlebar hit the tree and it bounced me back towards the creek, I feel on my back into about 3’ of ice cold water. I remember seeing the after close in around me and then jumping up taking a big gasp. Man, was it cold!
If it wasn’t bad enough to have fallen into th creek as the ride leader, there happened to be a March of Dimes Walk-a-thon on the same day on the paved path uphill from the creek. One of the walkers saw be jumping back up out of the creek and asked “Did you mean to do that?” Oh, yeah. Sure. I just jump into creeks in March for fun!
Worse yet, I had to ride the rest of the ride dripping wet...in March!