Sky lanterns, aka flame-retardant paper hot-air balloons, are set off in Thailand to commemorate special nights -- and a cluster of them can make for a crowd-pleasing cap to a nighttime event. The lanterns rise, glowing, for a few minutes, and fall when the fire goes out, then biodegrade quickly where they land. They're considered safe, but make sure that local fire ordinances permit them, that there's no danger of forest fires in the area and that it's not windy out. They cost $12.75 each here. Thanks to Girl Admiral Events in Fairfield, Conn. (203-257-7323; girladmiral.com) for spotting the idea.