I see a future not so far away. We want to build cities faster and farther; in space, on the moon. We need resources. We turn to machines to fabricate and construct. The world of men is made up of downloaded buildings constructed by generic self-replicating robots. We start to see memes in form and shape. Every possible idea has been invented. We joke about houses and cities made of designs literally copied and pasted from others. The human race spreads across the universe and we are just as dull and bored as we are today. The stars go out, the lights dim, entropy consumes all structure and order; all the energy in the universe is spent; all the potential exhausted.
The last man sits in a chair sipping some forgotten vintage and watching the end of the universe creep closer. He knows this will be the last idea. The last thought. And before he can formulate it, he sees that its realization was, in itself, its own end.
He laughs, and with that, the world neatly ends.