Top Ten Most Polite Ways to Tell A Guy His Zipper is Down...
 

By David Letterman.

10. The cucumber has left the salad.
9. Quasimodo needs to go back in the tower and tend to his bells.
8. You need to bring your tray table to the upright and locked position.
7. Paging Mr. Johnson....Paging Mr. Johnson....
6. Elvis is leaving the building.
5. The Buick is not all the way in the garage.
4. Our next guest is someone who needs no introduction.
3. You've got a security breach in Los Pantalones.
2. Men may be from Mars...but I can see something & it rhymes with Venus.

1. I always knew you were crazy, but now I can see your nuts! :D

I would think the most polite way would be with a kiss.

Oh back in my day all we had to do was just say XYZ and dang nab it, people understood.

But now if my fly is ever down and someone spots it before me I say witha straight face "I know, I prefer it that way."

Those are pretty decent ones, but I like Yakk's version. Though, where would the kiss be planted...or is my assumption correct... ;)

rofl.

Although im rather tactless, i say something along the lines of "Your zipper is down".

I prefer "You're in Monica mode instead of Hillary mode."