"Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy an utterly insignificant little blue-green planet once orbited a small unregarded yellow sun. The planet's cetacean life forms were so amazingly advanced that they decided not to climb gasping onto the land, grow fur and evolve into apes, but instead returned to live in its ocean deeps, playing, eating, playing, sleeping, playing and singing songs. Playfully."
(Picture originally from here. Text by Dirk Maggs, and possibly Douglas Adams too, although I don't recognise it from the books...)
So long, and thanks.