Well here's some good news.has just released one for its sci-fi extravaganza Civilization: Beyond Earth. Check out if you have the space-age future tech necessary to run it.
Actually, Beyond Earth is far from the most demanding game available these days, but for anyone whose PC is a bit behind the times demos are invaluable. So well done Firaxis, and all you other developers take note. The demo will let you play around 100 turns, which is barely enough to scratch the surface of what Beyond Earth has in store, though it'll give you some idea of what to expect.
Head on over to the game'sto download the demo. It's only 5GB, so it shouldn't take you too long to grab it.