Claire mentioned these Glo Gloves on Usenet at wreck.bikes.misc. They're reflective gloves that you can wear either alone or over other lightweight gloves. They're one-size-fits-most Spandex that stretch over your hands or undergloves.
Two models appropriate for cyclists are the Original (shown here) and the Sport (with padded palm and inside reflector moved to the wrist).
If you're riding at night, you're probably also riding in cool to cold weather so the utility of these gloves seems limited. If you ride at night in mild conditions, however, these bright reflectors seem ideal to boost your conspicuity. Suggested retail runs $23 to $25; online retailers charge about $20 to $22.