Whaddaya mean, you've never had monkfish liver? Roy Villacrusis, sushi chef at Mark's CityPlace, claims it's the "foie gras of the sea." Of course, you'll have to taste it to believe it, and now you can do that not only at CityPlace but at Mark's Mizner Park (344 Plaza Real, Boca Raton, 561-395-0770), where Villacrusis recently implemented his innovative sushi menu. If you're not quite adventurous enough for fish organs but still want high quality, rest assured your tuna roll will be waiting -- except that it might be made with bluefin tuna from Hawaii. And your sashimi just might be swordfish. And your bill just might be outrageous. But if that's the price we have to pay for foie gras from our finned friends, so be it.