"Think of brain tissue the same way you'd think of your bone density," begins Bruce Friedman, completely unaware of the fact that we never think of our bone density. "Your mental capacity grows in the same way till you turn 30. From there, your mind deteriorates, same as your bones."

But there's good news. According to Friedman, the stone genius behind mybraintrainer.com, doing certain exercises can actually strengthen your gelatinous gray matter. Below, he shares a few tricks for ramping up your intellectual dexterity. For those of you who are already too smart for your own good, we've tossed in a couple of teasers that will bring you down to our level.

Brain boost Select 10 letters at random (seven consonants, three vowels). See how many words you can spell with these letters in one minute. Score: 5–10 words, keep trying. 15–25 words, you're good to go.
Brain bust Watch 24 hours of Wheel of Fortune (without blinking), paying no attention to the letters. Instead, focus on the growing size of host Pat Sajak's cranium.

Brain boost Place three cups in front of you: one red, one blue, and one yellow. Turn on talk radio. When you hear the word the, point to the red. I gets yellow. She/he gets blue. See how fast you go. Score: Choose the wrong cup 10 times per minute? Keep trying. Fewer than three times and you're good to go.
Brain bust Place two jugs in front of you. One empty, the other filled with your favorite beverage. Transfer liquid from one jug to the other—by way of your urinary tract.

Brain boost Turn a page from the magazine upside down. Read from bottom to the top as fast as you can. Score: More than four minutes per page, keep trying. Less than two, you're good to go.
Brain bust Pick a page from Reader's Digest and read it.

Brain boost Start with the number 750. Deduct 7, then deduct 7 again and so on as fast as you can. See how far you can progress in one minute. Score: Made it to 694? Keep trying. 638 or lower and you're good to go.
Brain bust Start with the number 6. Flip it over and shout the numeral it most resembles as many times as you can in one minute. —SB