Mr. Rewrite would love to say it's difficult to criticize The Washington Post, but in reality it's sort of fun. Here's an error that's come up quite a bit in the broader media's coverage of Gabrielle Giffords' amazing and inspiring recovery: making her last name possessive as Gifford's. The Post blog highlighted above has just one of the botched references in today's stories (see the rest).
Mr. Rewrite sort of understands the difficulty here. Writers think singular possessive, see the end of Giffords' name and have brain cramps. The correct style can be Giffords' or Giffords's, depending on an organization's preference. The AP Stylebook, which Mr. Rewrite follows, goes with just the apostrophe when a proper name ends with S.
By the way, the plural for Giffords is Giffordses. The plural possessive, per AP style, is Giffordses'.