Another English variant is "Dude... x y and z." "Z" being an abbreviation for zipper. I once had my fly down and an old man told me that "my barn door was open." I thought that was pretty funny.

Aussies say: "Your fly's undone mate..... you might want to zip it up"

The zipper on pants is normally referred to as "fly" The most common comment is, "Your fly is open." http://www.linkydinky.com/flyisopen.shtml

In Indonesian language, "ritsliting Anda terbuka". The word "ritsliting" or "retsleting" that we use in daily conversation for "zipper" is adopted from Dutch word "ritsluiting".