I was photographing a ribbon cutting this morning and there was another person there with a DSLR. As I was browsing a shelf full of super expense eyeglass frames, I heard a sound of glass smashing on the floor. Naturally I thought someone had dropped some eyeglasses. It was the woman's (Canon) lens, fallen clean off the camera body! I have no idea how that could have happened. The only glass that broke was that of her UV filter. However, a portion of the front ring element was bent inward so unscrewing the remaining parts of the filter were not possible.
A few years ago I was teaching a DSLR Photography Lesson in downtown when someone with a big camera bag walked past. About ten seconds later I heard a crash. Her (Canon) lenses had fallen out because the bag was not closed all the way.
This is where I got the idea for today's poll question. If the unfortunate has happened to you, please tell us the circumstances surrounding it in the comments below and if your lens(es) were able to be fixed. If you have never had any lens break, also let us know why you think that is.