File this under "no duh" studies: If another sleep-deprived day in the office has you looking for that elusive nap room, look no further than the kitchen coffee. Though coffee has gotten a bad rap, fatigue in the workplace raises your risk of making mistakes and, depending on where you work, getting injured. A study of sleepy shift workers found that nothing was more effective than caffeine at preventing on-the-job errors — (somewhat surprisingly) not even prescriptions for alertness or naps. Next time you start falling asleep at work, drink up! But er, you probably knew that already.