You can profit by telling it onstage at a comedy club. You can't police every standup act in the nation.
I think legally, the second you create something original, you technically have a copyright on it. Don't quote me on that though.
I don't see how changing the word "seepage" to "leakage" made Jeff Foxworthy's Side Effects joke any funnier.
Many don't "see" how such a word improves the joke. This is mainly due to the fact that those that recognize its origin are covering their eyes with their facepalming.
[carlos] hey guys, im mexican and shit, im like a nonfunny george lopez, vagina vagina!! Har har [/carlos]