Update: As commenter Bart points out, this ad first went up on Paul's Youtube channel a month ago. For some reason, the campaign posted it again yesterday (the upload date for the below version of the "Three of a Kind" ad is Feb. 28, 2012; the first pub date was Jan. 16, 2012). Unlike most of the Paul campaign's ads, however, this ad is "unlisted"; meaning "only those with the link can see it." My guess: The Paul campaign uploaded and circulated the ad again to convince campaign reporters that they are not colluding with Romney.
Original: Ron Paul's campaign has released an ad attacking Gingrich, Santorum, and--yes--even Romney.