What do you call the son of your mom's cousin? How about the husband of your mother's uncle's daughter? Type how you're related into Wolfram Alpha's computation engine, and it returns the relationship—first cousin once removed, in that last example.
Not only do you get a sketch of the family tree when you enter something like “great-uncle’s son’s daughter,” but you get a quick chart explaining just how related you are to the person you’re describing, in a “blood relationship fraction.” You may now proceed to whittle down your holiday card list, as well as impress everyone with your proper genealogical naming at the family reunion.
Update: Kane2742 points out that “Cousin” on Wikipedia explains the first, second, X-removed, and other particulars of relationship naming in writing, as well as on a nifty chart.

Nice post. All very good suggestions. OMG, I have to digging it immedidately.
oil spills should be controlled as soon as possible to prevent environmental damage*.*
oil spills can really damage the environment so bad that it would take years to repair the damage`”
oil spills always do great environmental damage and it would always cost millions of dolalrs to repair ”