To celebrate April Fools' Day, Bethesa has announced that for the next week all downloadable content for The Elder Scrolls IV: Oblivion is on sale for half price. So that means you can pick up things like "Knights of the Nine" for 400 MS Points or "The Vile Lair" for 75 MS Point.
But if you want the legendary "Horse Armor" DLC, you're going to have to spread your wallet a little further. In honor of the upcoming third anniversary release of the content (April 3), Bethesda has doubled the price. That's right, now what has become a running joke in the industry as a way not to do DLC will cost you 400 MS Points for the next week. Why? Because it's funny. Oh, and you weren't going to buy it anyhow. (But I wonder how many people actually will?)