Note: I'm going back and giving each prompt a number based on the date it was posted.

When I'm slow to get started on the writing of a poem, sometimes I'll use the old technique of beginning a statement with "Because…" or "And then…" and repeating until I have a page full of lines as raw material. Even though, in some instances, the poem would work leaving "Because" or "And then" at the start of each line, I usually wind up removing them.

For the #716 SPAM poetry prompt, I suggested writing 15 lines starting with "big summer sale" but added that you could write more or fewer lines--the 15 was an arbitrary number. The first thing that came to my mind when I wrote down "big summer sale" was the sidewalk sale they held at the mall (i.e., shopping center) where I hung out as a kid. I started writing, and when I'd run out of steam and began repeating myself, I went back and counted up 22 lines:

Big summer sale was a sidewalk sale.

Big summer sale took place at the shopping center.

Big summer sale gave the stores a chance to sell a lot of junk

     for very little.

Big summer sale touted itself as a parade of bargains.

Big summer sale never began on time.

Big summer sale always took place on the hottest day in August.

Big summer sale had nothing of value.

Big summer sale got crowded on Saturday afternoons.

Big summer sale got in the way.

Big summer sale was a treasure hunt.

Big summer sale put merchandise in bins and piled on tables outside

Big summer sale was where we found a big map of the New York  

     World's Fair of 1964 for a quarter.

Big summer sale also offered ice balls and cold drinks for sale

Big summer sale was full of colored pennants

Big summer sale wasn't as big as we thought.

Big summer sale lasted two days

Big summer sale was a promotion to attract customers to the

     shopping center

Big summer sale was a source of endless fascination

Big summer sale never materialized

Big summer sale burned hot as a grilled dog over white coals

Big summer sale was a lot of fun

Big summer sale was a good place to waste money

I removed "big summer sale" from the statements without reading them, then looked over the source material I had. I could have worked from that list as it was, but I decided to condense the statements into a paragraph:

was a sidewalk sale took place at the shopping center gave the stores a chance to sell a lot of junk for very little touted itself as a parade of bargains never began on time always took place on the hottest day in August had nothing of value got crowded on Saturday afternoons got in the way was a treasure hunt put merchandise in bins and piled on tables outside was where we found a big map of the New York World's Fair of 1964 for a quarter also offered ice balls and cold drinks for sale was full of colored pennants wasn't as big as we thought lasted two days was a promotion to attract customers to the shopping center was a source of endless fascination never materialized burned hot as a grilled dog over white coals was a lot of fun was a good place to waste money

I wasn't thinking about writing a prose poem necessarily; I just found it easier to organize my thoughts doing it this way. I then went through rearranging statements and crossing out those that were repetitious or that I thought would take the poem in a different direction from the one that was beginning to form:

was a sidewalk sale was full of colored pennants always took place on the hottest day in August burned hot as a grilled dog over white coals touted itself as a parade of bargains lasted two days was a promotion to attract customers to the shopping center took place at the shopping center gave the stores a chance to sell a lot of junk for very little put merchandise in bins and piled on tables outside never began on time had nothing of value got crowded on Saturday afternoons got in the way was a treasure hunt was where we found a big map of the New York World's Fair of 1964 for a quarter also offered ice balls and cold drinks for sale wasn't as big as we thought  was a source of endless fascination never materialized was a lot of fun was a good place to waste money

From here I began to write and shape the poem. I let it cool over the weekend, did some tweaking, then completed the piece. I wound up taking out an entire stanza (about how we kids shopped at the sale) because the details weren't that intriguing and it detracted from the poem overall.

Here's what I determined was the "finished" poem for the purpose of posting it here as a response to the prompt. If this were a poem I planned to submit for publication, I'd let it cool for a few weeks and tweak some more.

A Map of the New York World's Fair 1964-65

The big sidewalk sale, festooned in colored pennants,

was a medicine show spread up and down

the open air sidewalks of Hyde Park Plaza. 

It rolled out on a hot August Friday

and fleeced the shoppers until Saturday evening

with tables and bins spilling goods the merchants

had selected with an eye toward slashing their inventory,

or to whet the appetites of more discerning shoppers

who passed into the stores in search of something

that was worth spending money on.

Sometimes my mother purchased a generic,

utilitarian item at a discount--a pack of string dishrags

or a large bottle of aspirin. My father,

who believed an old promotional key chain

for a penny was found treasure, pawed enthusiastically

through the tangles of junk and was never disappointed.

He was especially proud of a dented cardboard tube

without a cap, something mysterious rolled up inside.

He paid a quarter. At home, he labored

with pliers and a butter knife until he'd extracted

an enormous map of the New York World's Fair.

It filled half the dining room table. We examined it

with a magnifying glass, reading the names

of pavilions and attractions, marveling at the

enormity of the exposition. None of us had ever

been to NYC, the fair closed in a few months,

but the map was as exotic as an atlas of Mars.

"And it only cost a quarter," my father repeated,

flushed and pleased. "I only paid a quarter!"

If you're interested, here's the stanza I deleted from the poem:

With change pried from our banks or doled from parents

who wanted us gone