Anyone who likes stand-up knows about Bill Engvall's "Here's Your Sign" jokes. But just in case, here's a sampling:
http://youtube.com/watch?v=U5ywQv2gnC8
One that's happened to me a lot last summer:
I bike to work all the time, and when I get in, I'm a little flushed, and carrying my helmet. Every now and then, a colleague would see the helmet and say, "d'you bike to work?"
...nope, just raining coconuts!
Heeeere's your sign :)