Has Daylight Saving Time messed with your bedtime? Or perhaps the tumbling stock market has you tossing and turning past lights-out. Or maybe, just maybe, you can't sleep because of that "decaf" you ordered at dinner.

A long-standing debate among the caffeine-wary is whether decaf served in restaurants is actually what it's billed to be—or is really a cup of the high-octane stuff? Are you among the wide-eyed skeptics? Read on.

Do-it-yourself caffeine detectors called D+caf Test Strips will tell you if your beverage is—or isn't—the real thing. Just stick one of the tiny strips into a spoonful of coffee or tea (sans any milk or sugar, which eliminates drinks like lattes and sodas) and you'll have your answer in less than a minute, according to Discover Testing, which makes the strips. If the line above "D" (decaf) on the strip is darker, you're good to go; if it's darker above the "C" (caffeine), beware—your drink probably contains more caf than you'd like.

Java is known to give some people the jitters if they drink too much of it. But can it also trigger hallucinations?

It may if you consume enough of it, say British psychologists, who report in the journal Personality and Individual Differences this week that college students they studied said they sometimes heard faux voices after chugging at least seven cups of coffee daily.

But the Durham University researchers acknowledge that their study of 219 coeds doesn’t prove that caffeine, a stimulant in coffee, actually caused them to hallucinate.  For instance, the students who reported hearing voices may have had psychological disorders and been chugging cups of, in this case, instant coffee to help them cope with symptoms, write study co-authors Charles Fernyhough, a developmental psychologist, and grad student Simon Jones.

Raise high the coffee bean! Good news, coffee-drinkers: a new study shows your beverage of choice may lower your chances of getting oral, esophageal and pharyngeal (back-of-the-throat) cancer.

Japanese researchers report in the American Journal of Epidemiology this week that people they studied who drank a cup or more of Joe daily had about a 50 percent less chance than non-imbibers of developing these cancers.  The scientists based their findings on 13 years of data of some 38,000 people ages 40 to 64 with no history of cancer.

According to the study, coffee drinking lowered the odds of these types of cancer even in people with high-risk behaviors (read: smoking and boozing).

"Caffeine has been suggested to suppress the progression of tumor cells," senior study author Toru Naganuma, an epidemiological researcher at Japan's Tohoku University, told ScientificAmerican.com in an email. He noted that other studies have also linked moderate coffee drinking to reduced risk of liver cancer.

Researchers from the University of Nevada, Reno, have discovered that coffee can be turned into an alternative fuel other than caffeine: biodiesel. And you can have your coffee and drink it too. No need to use the fresh stuff, old grounds are more than up to the task, according to material scientist Mano Misra and his colleagues.

Even after being subjected to the rigors of brewing, roughly 15 percent of the weight of dried coffee grounds is oil, which, much like palm and soybean oil, can be converted into biodiesel. The coffee has the added benefit of not being a food source, like palm oil and soybeans.

Nevertheless, more than 16 billion pounds of coffee are produced globally every year, according to the U.S. Department of Agriculture. Misra estimates that the grounds from that haul could be used to make as much as 340 million gallons of biodiesel. For their part, the researchers turned grounds donated by Starbucks into biodiesel that had the added advantage of smelling like a fresh cup o' Joe.