Rise of Nations: Extended Edition, for myself and my friend, £3.75 (75% off) each.
We've been waiting for well over a year to get this now.
It was my favourite RTS and I kept going on about it while we were playing the likes of Age of Empires. But the price has been stupidly high for a long time, and I missed the last time it was on sale for a good price.
Unfortunately my friend happens to be in Denmark at the moment and not watching Steam, so I bought it for him just in case!
Also, is this called the Thanksgiving Sale for you guys in America, or are they also using "Exploration Sale" as its title, as they are for me?