First off, I thought you brave puzzle-solvers (and fans of the National Treasure film series) would enjoy this article from yesterday's Wall Street Journal. After more than 200 years, a mathematician successfully decrypted a code text that had been sent to Thomas Jefferson.

Today's Brain Game isn't nearly as difficult; you'll start with a single letter of the alphabet and build into a seven-letter word. You'll accomplish this by adding one letter of the alphabet to the mix with each entry, and (if necessary) rearranging the existing letters, to form new words. (Example: I, IN, NIP, PINS, SPINE...) Good luck!

1-letter word: a type of boat
2-letter word: a Weekly magazine
3-letter word: see first clue
4-letter word: a baseball team
5-letter word: a diving aid
6-letter word: a math aid
7-letter word: an Italian liqueur

Here is the SOLUTION.

THE SOLUTION:

U, 
US,
SUB,
CUBS,
SCUBA,
ABACUS,
SAMBUCA.