Civilization V is one of the best strategy games available on PC, and it's even better now that the first true expansion pack - Gods & Kings - is available for purchase. It comes with a whole bunch more civilizations, units, buildings and scenarios plus some new gameplay mechanics that enhance the Civilization V experience.
However if you're unsure about paying a whole $29.99 on the expansion pack (or a whopping $49.99 in Australia!), a demo is now available to download via Steam. Head to the source link below to queue up your download, but a reminder that you do need an existing installation of Civilization V as this is not a standalone expansion pack.