When winter lasts the better part of the year, shedding that extra December poundage can be daunting. Jim and Marcia Rosati of Rosati's Frozen Custard aren't helping. Once it heats up, that's when you remember they've whipped up more than 100 fabulous flavors of silken, old-fashioned frozen custard -- lush, sweet, and churned fresh hourly. And with only eight or so flavors featured each week (including possibilities like Whitehouse and Drumstick, pistachio and Peach Melba, and a mouthwatering rendition of Higbee's Chocolate Malted -- so popular it usually shows up twice) and three different outposts to visit, one's always within reach. Our suggestion: Jog there.