Direct2Drive is hosting a discount program that seems very similar to Steam’s current promotions. I’m not sure how long it will last, but they’ve marked Civ V down to 29 bucks, which almost makes it a good deal to grab some of the DLC while you’re at it.
UPDATE: Sorry, guys – I guess this deal ended very quickly. For those of you that missed it, I’ll keep a look out for any other sales. Feel free to follow the link in the “Gaming Links” menu above and browse the site – they are doing some pretty awesome deals right now overall.