Ring of the Early Riser (3.5e Equipment)
From D&D Wiki
The wearer gains the benefit of a whole night's rest in half the time. For races that require sleep to naturally heal, regaining lost hit points and ability damage, the wearer only need 4 hours of sleep instead of 8. For races that meditate, such as elves, only 2 hours are needed.
The ring must be worn for an hour before it becomes attuned to the wearer and takes effect.