I sometimes go a little too far in my belief that most questions have black & white answers (hah!). But on this one, it seems easy. Don't do it at work. You might have the funniest racially-charged joke on the planet, and if you told it, everyone within earshot would be convinced you were the wittiest guy alive. Don't tell it at work. Seriously. Why is it necessary?

Other than that, do what you want to. Unless you're a public govt offical(sorry, anything you say in public counts as being "at work" - you get plenty of other perks to make up for it), what you say on your own time is your own business.