First Look has the article Passphrases That You Can Memorize — But That Even the NSA Can’t Guess.

I’ll quote just enough of the article to give you a hint at how secure it is and how different it is from what you may be thinking.

In other words, if an attacker knows that you are using a seven-word Diceware passphrase, and they pick seven random words from the Diceware word list to guess, there is a one in 1,719,070,799,748,422,591,028,658,176 chance that they’ll pick your passphrase each try.

At one trillion guesses per second — per Edward Snowden’s January 2013 warning — it would take an average of 27 million years to guess this passphrase.

Not too bad for a passphrase like “bolt vat frisky fob land hazy rigid,” which is entirely possible for most people to memorize. Compare that to “d07;oj7MgLz’%v,” a random password that contains slightly less entropy than the seven-word Diceware passphrase but is significantly more difficult to memorize.

I am thinking about using this technique myself.  Just remember, if you use the exact pass phrase quoted above, it will not be secure at all.  You have to use the technique to generate your own random pass phrase.