Here's a great blog composed entirely of reader-submitted stories that are only one sentence long. A few of my favorites:
I didn't recognize the voice or the number, but the message said, "I just thought you might like to know I'm pregnant."
Thank you, guard rail.
Our first kiss tasted of Lucky Charms.
Here's one of my own:
My lawyer was having a hard time convincing the jury that the man in the Chuck E. Cheese outfit really did appear to be drawing a gun out of his vest.
Add your own in the comments. Unlike One Sentence, I won't claim your stories as my intellectual property.
UPDATE: As I read through the addictive archives, I've found this online anthology to be remarkably similar to Post Secret -- another blog that you should be reading weekly, if you aren't already.