http://store.steampowered.com/Steam is doing a sale on games! I think they're downloads only but I'm not entirely sure.... But Civilization 4 plus all the expansions for $14? I'm sold.
*EDIT*
It is a download and you need to have a steam account that you use. You'll need to use the steam you account you bought it with, log in the steam client and it will be listed under "My Games" tab for you to download there.
There's also an option for "buy for a friend" or something like that when purchasing. Not sure how that download will work.