"It can only be the thought of verdure to come, which prompts us in the autumn to buy these dormant white lumps of vegetable matter covered by a brown papery skin, and lovingly to plant them and care for them. It is a marvel to me that under this cover they are labouring unseen at such a rate within to give us the sudden awesome beauty of spring flowering bulbs. While winter reigns the earth reposes but these colourless green ideas sleep furiously."
A beautiful - poetic even - couple of sentences from a competition to give meaning to the famous sentence "Colorless green ideas sleep furiously." through context. The sentence, invented by Chomsky, was intended to demonstrate that there are effectively uninterpretable sentences that are nonetheless syntactically well-formed (i.e. they "sound fine" even though they make no sense). The problem being that you can show that pretty much any such sentence is not just interpretable, but easily interpretable under a reasonable context.