This isn't an April Fool, folks. Microsoft have slashed the prices of two games and a piece of DLC for today only, meaning that you need to get involved sharpish.
The most important reduction is that Dead Money, Fallout: New Vegas' first expansion pack, is now 400 Microsoft Points. You absolutely should buy it. Seriously. Check out my review if you have any doubts.
Comic Jumper and Deadliest Warrior are also down to pocket money prices, but I can't wholeheartedly recommend either of them. For all of its pretension, Comic Jumper is a repetitive and ultimately boring twinstick shooter - and Deadliest Warrior is extremely mediocre. Still, they're also extremely cheap.
Click the links to check out the savings and queue up the downloads!