There's a small lake in San Francisco's Golden Gate Park, Spreckles Lake, used for model boats and such on weekends. It's a couple of acres, but not very deep. How do I know it's not very deep?
Well, one day when I was a teen, a friend let my try his new 10 speed bicycle. This was in the 60's, when 10-speeds were still considered fairly exotic. Anyway, I was cycling around Spreckels Lake, when I started fiddling with the gear shift levers. The lake has an asphalt paving all round it, and the "shoreline" is sort of wavy, with lots of inlets and outlets. The sides of the lake are nearly vertical, to help people sail their models right up to the edge.
Well, I suppose the next thing that happened was inevitable. I lost track of the shoreline, looked up from the shifters, and saw that I was headed straight into the lake. There was nothing I could do! So the bike and I went over the edge, sailing into the water. I think I did a back flip off the bicycle, and landed on me feet. The water couldn't have been more than four feet deep, but enough to get me soaked from heat to toe - not to mention the brand new bike. An man saw the whole thing and was bent over laughing.
I said nothing when I came back to my friend, but of course he noticed my sopping wet clothes. I could have gone home and changed and disguised the event, but I felt it was better to fess up. The bike was basically undamaged except for being wet. He was a bit po'd at the whole thing, but he kept on laughing every time he looked at my sopping wet clothes and hair, and let it go.
Years later when I bought a new 10 speed bike, it had shifters at the end of the handlebars... for a reason!