Give bubbly a boost with jewel-like cranberry-, pomegranate-, and apricot-infused sugar cubes. Working in batches, soak cubes in a bowl of fruit concentrate or puree until completely saturated. Remove with a fork, and place on a wire rack (don't let them touch); let dry overnight. Present cubes at a champagne bar, or serve them in passed drinks. The sweet, tangy taste will keep guests sipping long after the toasts.