There's a pretty good sale running on Xbox Live right now. Starting today and running until April 4, the "Extreme Shopping" promotion has dropped prices on many Xbox Live Arcade games, DLC add-ons and Avatar items. Some of the highlights include Alien Breed episodes 1 and 2, Monkey Island 2, Defense Grid, Darwinia+, Doom 2 and Crazy Taxi all for half price at 400 points ($5) each. Costume Quest can also be had at half price, 600 points ($7.50).

Also up for grabs, all Halo Wars DLC has been knocked down to 400 points, as has Red Dead Redemption's Undead Nightmare pack. Or, if you're feeling frisky, the entire Undead Nightmare Collection has been reduced to 1000 points ($12.50). Finally, MS will also be offering some special one-day deals on April 1, though exactly what those offers will be is a mystery for now.

Oh, there's also a cheap Avatar Chewbacca costume. You know, in case you've been wanting one, or something. Hit the source link for all the current deals.

Update: As commenters have noticed, Major Nelson has posted the one-day deals for Friday, April 1. They are:
  • Fallout: New Vegas Dead Money Add-on 400 MS Points ($5)
  • Comic Jumper 400 MS Points ($5)
  • Deadliest Warrior 200 MS Points ($2.50)
  • Fable 3 Understone Add-on 200 MS Points ($2.50)

This article was originally published on Joystiq.