The party animals arrived two by two. They came earlier this month, more than 2,300 sets of twins—some identical, some most certainly not—converging from all over the world on Twinsburg, Ohio, for the town's 14th annual Twins Days Festival. The former womb mates plunged into 104 contests, in categories such as most alike and least alike, youngest (2½ weeks), oldest (89½ years) and born farthest apart. The turnout was enough to break the twin-convention mark in the Guinness Book of World Records, set at last year's Twinsburg gathering.