THE JONATHAN AMES AND MOBY VARIETY SHOW. Hurry up and snag your $15 tickets if you want to see those crazy chromedomes offer their "Dick Cavett/Smothers Brothers-style show" at 7 pm and 10 pm tonight at Ars Nova in Hell's Kitchen. Just remember to bring your top hats and monocles, fellas--"cocktail attire" is requested. (The performances are to be taped for television, which we all know is very classy.)