Reading this, I just thought of another way to make passphrases that might be a bit more memorable. The idea is to come up with a sentence which will be grammatically correct, so it'll be easier to remember.

First, write down 36 words. Roll two dice, take six times the number on the first minus the number on the second plus one. That is the position in the list of the first word in the sentence.

Next, write a new list of 36 words, but only include words that make sense given what is already there. Roll again as before and pick as before. Reusing words between lists is fine, but don't include the same word in the same list multiple times.

Rinse and repeat until you have the desired amount of entropy. Each die thrown adds log_2 6 bits.

Edit, just tried this, 36 is a lot of words to come up with. Much easier to write down 6 at the cost of making it twice as long. Unless you have access to lists of nouns, verbs, etc.

Bored now, but came up with "Countries can slowly sit at my feet", 24 bits of entropy (some lists had 36 words others had 6. It's very low, but, if you did that 2 or 3 times, you'd be getting somewhere). Couldn't be easier to remember.