Civilization V demo out now
A genteel introduction.
A demo for Civilization V is available right now on Steam.
You need to paste the URL steam://install/65900 into the service's address bar to find it, according to a post on the Civ5 forum [No you won't - there's now a proper download option on Steam -Ed.].
The official website makes no mention of the demo, despite a press release touting its availability.
Civilization V will be released on Friday. Eurogamer's review will appear later today.