I have succulents on my balcony that outgrow their pots. I break off chunks long enough to have a few root-hairs attached and drop them into the scruffy area at the side of the building. They can't really root themselves there unless we get a bunch of rain, but I've seen a few people take one and it always makes me happy.

Yeah, I've got a couple succulents, and leaves will fall off and propagate on their own in the pot pretty often. All they really have to do is fall stem-side down into the dirt and it'll grow roots and form a new plant. I just gave my buddy a small jade plant that grew from my larger plant that was originally itself a small auto-propagation from my dad's plant.