Just pick a scent you won't get sick of. And apply in bursts.

Just in time for the mother of all memory tests (too bad BarBri didn't attach a business practices patent to this idea before word got out):

Scientists studying how sleep affects memory have found that the whiff of a familiar scent can help a slumbering brain better remember things that it learned the evening before. A rose bouquet — delivered to people’s nostrils as they studied and, later, as they slept — improved their performance on a memory test by almost 15 percent.

No freaking way.

The brain is thought to process newly acquired facts, figures and locations most efficiently in deep sleep. This restful state usually descends within the first 20 minutes or so after head meets pillow, and it may last an hour or more, then recur later in the night. The researchers delivered pulses of rose bouquet during this slow-wave state; the odor did not interrupt sleep, and the students said they had no memory of it.

But their brains noticed, and they retained an almost perfect memory of card locations. The students scored an average of 97 percent on the card game, compared with 86 percent when they played the concentration game and slept without being perfumed by nighttime neuroscience faeries.

Evidently, olfactory sensing pathways lead more directly to the hippocampus than visual and auditory ones. Who knew? So we'd be way better off inhaling those PMBR flashcards than just staring at them. Where do I get a nighttime neuroscience faerie? Is that like a sprite?