I'm fond of the Jack-and-the-Beanstalk story; a few casually discarded beans led to a goose that laid golden eggs, and a singing harp…
It's only a slight exaggeration of the magic contained in ordinary things; the moral Jack was to derive from the story was that one mustn't underestimate the potential of small things - actually, I think Jack was so guileless he didn't even need to ponder that, but his mother needed convincing. Perhaps she was convinced; I'm also fond of versions of the story which have her ignorantly making cacciatore from the goose Jack brings home…

Several years ago, a fellow I knew casually was in distress, and asked me for help.
He had come to my island from Philadelphia thirty years prior to be a garlic farmer, but although he raised a successful garlic crop, he declined to grow it commercially after all.
Years went by; he saved out good bulbs to use for seed each year, and grew a nice crop.
Then, he met a woman who lived, frequently, in Hawaii, and began to live there with her, more and more frequently, to the point that he was there nearly year-round.
He continued to grow garlic on this island, having set up an automatic watering system which drew from his well.
One year, though, his well failed, so although the system opened valves to water the garlic, no water was coming out of the ground; dehydrated garlic still grows, but the bulbs get small and rather angry, some of them nearly winking out of existence, if not merely being too small to mess with, let alone plant and expect anything.
So my Italian friend had nearly lost his entire crop, which he'd been faithfully growing for decades.  He didn't know what to do, so he called upon me.
At the time, I was, among other things, managing a garden at a retreat center - over twenty large, cedar raised beds, and a dump truck and tractor and concrete soil yard, so excellent compost, so my pal thought I could take what garlic he had and look after it.
He handed me his remainder, one handful of tiny bulbs, not even as big as an avocado pit.  Each one had four or five wizened cloves, so about thirty in all.  Rather tragic.
It was late summer; I promptly planted the garlic in the ground, although it's customarily planted in the fall (in fact, subscribing to a notion from a devout neighbor, I have planted by the moon for years, planting my garlic as soon after the moment of moon fullness as soon after All Soul's Day - so it's rather like calculating Easter).  These things were in critical condition, and needed moist soil.
I grew them in straight compost that year, and harvested some respectable bulbs the next summer.  They were a softneck and faintly blushed with pink; I allowed myself the luxury of eating one of the bulbs: pungent and assertive.  Nice garlic.
But I ate none of the others, and planted everything in the fall.  The soil I had grown in was rich, which garlic requires, and had enabled some large bulbs, some with fat cloves.  The garlic had great potential.
That year, I planted them in straight, hardly-aged llama manure.  It's a fantastic resource, if one has access to llamas: they cooperate by crapping in one spot in the field, or maybe two, so there's a central pile to load from; the manure is olive-sized pellets, which are easy to work with; you can put it on fresh, like rabbit manure, and it doesn't burn.
Those bulbs that year were outstanding.  I harvested about two hundred, as I recall, and saved most of them for planting.  I also entered them in the county fair that year - five identical specimens are required for entry, and I had five huge, uniform, gorgeous bulbs.  During the fair, I heard from friends, who wanted to know "what kind of elephant garlic was that you entered?" but it wasn't elephant garlic.  Just huge bulbs.
I won an award of merit rosette that year, which was far larger than the largest bulbs I grew, but what do you know?  When I went back at fair's end to collect my entry, it had disappeared.  Funny, the Superintendent of Vegetables was a commercial garlic grower… and it happened again the next year, which was my last.  Don't need rosettes.  Five bulbs are better.
The next year, I harvested over two thousand bulbs, large and uniform, and gave a bunch of it away to other gardeners to plant, and supplied all my needs and the needs of the retreat.  What had been a paltry ember had become a roaring blaze, and was being broadcast far and wide.  The garlic was in no danger of passing away.
I had also determined that it didn't have a name, and that the source, all those many years ago, was forgotten, so I got permission from the fellow who gave it to me to name it myself.
I called it Rosina, after one of my cats (who was named after one of Rossini's characters in Il Barbiere di Siviglia).  Now, people were growing Rosina garlic everywhere.
Magic beans, magic garlic…

My most recent experience with this amazing phenomenon came through my sister. She knew of my fondness for Wanda primroses (primula officinalis Wanda); they're the old-fashioned, prolific ones that get planted with King Alfred yellow daffodils around trees in the yard, masses of purple blooms in the early Spring.
They get planted as long borders, and I had always tried to cadge some from my step-mother's, but she was always using her surplus to fill in gaps in the border.
They're pretty accommodating when it comes to making offsets: each little plant will generate about four or five little ones, which can be carefully pulled from the parent in the late summer, grown on, and then planted out in the fall.
So I never had any - I'd see them, occasionally, at the nursery, but they were always expensive, like five bucks for a four-inch pot.  So I'd pass them by, since it would take so many to get a border going.

My sister gave me three of them as a Christmas present a few years ago, so that was, at least, a start.  I kept them in the four-inch pots, and planted them into gallons in the spring.
In the late summer, each one of them had made six or seven offsets, so I divided them into little pots, and planted them up into gallons in the fall.
You can see wehre this is going: each year, I patiently divided them, and grew the divisions on, some few months later dividing them, until I had enough to plant out.
I have a little bed with a large forsythia and an unfortunate old lilac - two years ago, a spastic ran into it when his car went off the road - actually, he was an epileptic, not a spastic (sorry if anyone was offended) - no idea why they let him on the road - so one large trunk remains, and is working really hard.
I dug out all the turf, and planted out about one hundred and fifty Wandas, from four-inch pots (which were available at the nursery at the time for five bucks, so I had a value exceeding six hundred bucks, if you can imagine me getting a quantity discount had I bought them).  Not only that, but I had two flats left over, and about twelve gallon pots I hadn't divided, so at least another two hundred plants.

Once I divide everything I have (including the two flats of four-inch pots), I'll have over three hundred plants, estimated conservatively, which, if I execute this during the spring, will generate more offsets by the end of summer, so I could easily coast into next spring with well over five hundred plants.  I'm already determined to donate five flats of them to a non-profit garden nearby, and what the heck?  Might as well sell a few…
So talk about the goose that laid the golden eggs, eh?
And this doesn't even include the paltry few seeds of "peasant" arugula (aka Silvetta) an old friend managed to send my way; now I have a jarful, and have given many away.  Same with lettuce seeds, and the list goes on.

Along those lines, I am also preparing to go out on my annual expedition to round up maple seedlings. 
I got interested in bonsai some years ago (will write about that profound topic another time), and a mentor I had stumbled upon suggested that landscape Japanese maple seedlings were a good source of material.   I had unsuccessfully tried to grow seedlings from seeds I had collected, but he suggested that I simply let nature decide which ones would grow, and go collect them.
I began doing that several years ago, and now, have some well-pruned, respectable small trees (once I put them in containers, they'll be bonsai; until then, they're merely small trees).  I also have a weakness for vine maples (Acer circinnatum), which are native in my area, and lovelier deciduous hardwoods are hard to find.
So I collect those as well.  They're a bit trickier to keep small, since they're fast-growing trees, but I also have let some of them put on size, and have planted a few out in my landscape, as well as maintaining a slowly-burgeoning nursery bed of them.
A woman I know is replanting a reclaimed area (reclaimed from the bramble, Himalayan blackberry, Rubus discolor, which is about the only thing around her you'd have to reclaim anything from) - she wants to put in natives, and asked if I had any vine maples for sale.
I think I can spare her some (got to get out and get some more to replenish my supply and feed my craving), but I also found out she bought a Western Hazelnut to plant in this hedgerow sort of area, and that she paid forty dollars for it!
Unbelievable.  I had to rip out some deck boards to liberate a Western Hazelnut that had been planted by a squirrel under there a year or two ago - as of last fall, it's planted out in the landscape, and flowered this last winter…
There are Hazelnut groves here in town, and many specimans here and there planted by the squirrels, both native and Eastern Gray, and also by the Steller's Jays.  They come up frequently in my yard, and one sees them - as well as English walnuts - coming up all around.
And yet, when I heard of this high price these common volunteers were fetching, I couldn't think of a grove of young ones I could liberate, but will just have to go out and look.  There's a conglomeration of Jays at one end of town, which isn't far from an old hazelnut orchard, so I suspect there must be a lot of young ones over there.