Mr. Rewrite was loading up on Super Sunday supplies when he spotted this sign at Costco: "Order YOUR'S Today." Yikes.
As Mr. Rewrite's latest video blog explains, never use an apostrophe to make a possessive out of a personal pronoun (yours, its, his, hers, theirs, ours are possessive on their own). Here's a better explanation of possessive personal pronouns than Mr. Rewrite could ever offer.
The most common error with a personal pronoun is it's when making a possessive out of it (use it's only as a contraction for it is). But the funniest errors, at least when the media make them, involve your's, their's, her's and our's.
Here's the carnage on Google News: