Go figure.

No, seriously. You must go figure, in one "Brain Age 2" minigame, the descending numbers correlating downward by seven from the number 78. And you must do so in very rapid order.

"Brain Age 2: More Training in Minutes a Day!" also makes you beat a quick clock while reading sheet music and pressing corresponding musical notes on a one-octave piano. This is not easy-peasy for nonmusicians.

Some "Brain Age 2" tests are somewhat less intimidating, like playing "Rock, Paper, Scissors."

Among the more moderately difficult minigames, you decipher how many dollars and coins to give back to a customer during a transaction.

But even those minigames gauge how fast you spin your logical mind, including sudoku puzzles. If you succeed quickly, the game says you have a young brain on the level of, say, a 22-year-old. If you're slow at math, you might have the brain age of a 55-year-old, even if you're much younger than that in real life.

Such logic games are awesome on the interactive DS, with its penlike stylus. Two other big winners are the summer releases "Picross DS" and "Nervous Brickdown."

"Picross" is a fill-in-the-blank puzzle, like sudoku but simpler. The board resembles "Battleship." There's an "X" axis and a "Y" axis, and you put a certain number of dots on each axis in a way that they correspond. I can't describe it any better than that.

It's a bizarre game with bizarre rules, and each round can last just 49 seconds or a full hour.

But trust me, "Picross" is mildly addictive if you're a math nerd like I am. (Most of my electives in college were calculus and such.)

Then there's "Nervous Brickdown" for the DS, a very creative and fascinating reinvention of "Breakout," the paddle-and-ball game. It comes with a handful of minigames, but what's exciting is how artistic these variations of "Breakout" are.

In one side game, you draw your own paddle shape (a "U," a "V" or whatever form you desire), and you push the paddle up and down (like you would on an air hockey table), and your ball destroys pretty, two-dimensional art paintings.

All these games are pretty cute, yet quite challenging. "Brain Age 2" is kicking my rump. On a weekend drive, my fiancee watched me playing it constantly and said, "You're gonna be, like, 18 by the time we get there." Nope. I had a brain age of 56.

I don't even want to do the math on how much older that makes my brain than my body.

("Brain Age 2: More Training in Minutes a Day!" retails for $20 for DS -- Plays addictive. Looks fine. Very challenging. Rated "E." Four stars out of four.)

("Nervous Brickdown" retails for $30 for DS -- Plays fun and cool. Looks great. Challenging. Rated "E." Three and one-half stars.)

("Picross DS" retails for $20 for the DS -- Plays intriguing if you're a math dork. Looks workaday. Easy to challenging. Rated "E." Three stars.)