“The Performers” offers proof positive that it’s possible to talk real dirty and still be the squarest show in town. Even in a season featuring two works by a king of Anglo-Saxon expletives like David Mamet, this comedy by David West Read may well clock the most obscenities per minute of any play on Broadway. Nonetheless Mr. Read’s perky account of innocents in porn land, centered on a film awards presentation in Las Vegas, feels like a throwback to the more discreetly risqué entertainments of 40 and 50 years ago. Though its author is only 29, “The Performers” is like an early Neil Simon farcewith an X-rated vocabulary, or a blue-tongued episode of the smirky but sentimental TV series “Love American Style.”…Mandrew’s wife and sometime co-star, Peeps...is played by Ari Graynor, who turns out to be Mr. Jackson’s ideal comic match. In endowing cartoon characters, whose punch lines are visible long before they land, with something like sincerity and spontaneity, these two work wonders. Unfortunately, with “The Performers,” wonders soon cease.