One time I clipped off a burnt shoot that got torched by contact with light, and after it had been in my pocket for more than an hour, I tossed it into a waste bucket that had a bunch of weed rootballs etc outside, and a few weeks later I realized it had 3 new nodes.. Had no convenient place to grow that though, so it got composted..
I also remember quite a few sprouts under the bleachers at my HS where ppl would sit and roll joints, and a seedling that was planted in a plant on the english teacher's desk by somebody that managed to define itself as pot to the point it was impossible to mistake before it disappeared..
(Oh, and to all the ppl out there who can't figure out how to keep seedlings healthy, that seedling did damn well on that desk just being left alone and treated like a houseplant..)