If you own one of the more popular rhythm games for Xbox 360, you're in for a treat. Starting July 6 and lasting thru July 12, a ton of DLC for Rock Band, Guitar Hero, and Lips will be discounted up to 50% of what they normally go for.
For Rock Band and Rock Band 2 owners, much of what's on sale is either packs or complete albums. If you're a fan of Foo Fighters, Megadeth, Pearl Jam, Red Hot Chili Peppers, or The Who, definitely look into grabbing complete releases from them.
Guitar Hero 5 and World Tour players may have more individual songs than packs to choose from but you guys can score the Rolling Stones and Metallica albums. Those who own Lips, Lips: Party Classics, or Lips: Number One Hits can get quite a few packs including by The Cardigans, Creedence Clearwater Revival, Marvin Gaye, Paula Abdul, and others. Hit up the source link for a complete list of discounts.