Rock Band 2 Cheats - Xbox 360

Cheat Mode
Go to "Extras"->"Modify Game" and enter the following codes:

[Yellow], [Blue], [Orange], [Yellow], [Blue], [Orange], [Yellow], [Blue], [Orange] - Awesome Detection.
[Blue], [Yellow], [Red], [Blue], [Yellow], [Red], [Blue], [Yellow], [Red]. - Stage mode.
[Red], [Yellow], [Blue], [Red]x2, [Blue]x2, [Red], [Yellow], [Blue] - Unlock all song.
[Blue], [Orange]x2, [Blue], [Yellow], [Blue], [Orange]x2, [Blue], [Yellow] - Unlock all venues.

NOTE: Activating cheat codes will disable saving.

Achievements
Complete each achievement to get the allotted gamerscore:

Along for the Ride (10) - Beat an instrument-specific challenge while playing another instrument.
AN-I-MAL!!! (25) - Beat the Impossible Drum Challenge.
Band Savior (20) - Be a savior three times during a single song.
Beat It! (10) - Complete all beats at 60 BPM or higher or half of the beats at 140 BPM or higher.
Challenge Master (15) - Complete 25 Challenges on Hard Difficulty or 10 Challenges on Expert Difficulty.
Fill Legend (20) - Complete all fills at 100 BPM or higher or half of the fills at 180 BPM or higher.
Fill Me In (10) - Complete all fills at 60 BPM or higher or half of the fills at 140 BPM or higher.
Flawless Drumming (25) - Score 100% notes hit as a drummer on Expert.
Flawless Fretwork (25) - Score 100% notes hit as a guitarist on Expert.
Flawless Groove (25) - Score 100% notes hit as bassist, up-strums only, on Expert.
Flawless Guitar Solo (20) - 100% a guitar solo on Expert, using only the solo buttons.
Flawless Singing (25) - Score a 100% rating as a vocalist on Expert.
Challenge Novice (10) - Complete either 25 challenges on Medium, 10 challenges on Hard, or 5 challenges on Expert.
Challenge Savant (25) - Complete 25 Challenges on Expert Difficulty.
Clothes to the Edge (20) - Buy over $100,000 worth of items from the Rock Shop.
The Bachman-Turner Award (25) - Maintain deployed Overdrive for 90 seconds.
The Beat Goes On (20) - Complete all beats at 100 BPM or higher or half of the beats at 180 BPM or higher.
The Final Countdown (15) - Unlock an Impossible Challenge.
The San Dimas 4th Annual Award (15) - Compete in a Battle of the Bands event.
Victory! (15) - Defeat a player in either Score Duel or Tug of War.
Virtuoso (25) - Beat the Impossible Vocal Challenge.
West Coast Performer (10) - Play a set on the West Coast of North America.
Western Europe Performer (10) - Play a set in Western Europe.
Comeback Kid (15) - Defeat the last player that defeated you over Xbox LIVE in either Score Duel or Tug of War.
East Coast Performer (10) - Play a set on the East Coast of North America.
Eastern European Performer (10) - Play a set in Eastern Europe.
Road Dog (30) - Play in every venue in the world.
Solid Gold, Baby! (25) - Gold Star a song.
Stage Igniters (25) - Beat the Impossible Band Challenge.
God Save the Band (10) - Play a set in the United Kingdom.
Got Wheels (20) - Win a Van in World Tour.
Groove Assassin (20) - Beat the Impossible Bass Challenge.
Heartland Performer (10) - Play a set in Middle America.
Hello Cleveland! (20) - Deploy Vocal Overdrive 4 times in a single song.
Jet Setter (20) - Win a Jet in World Tour.
Lord of the Strings (25) - Beat the Impossible Guitar Challenge.
Million Point Club (25) - Earn more than 1,000,000 points in a single song.
Needs more Umlauts! (10) - Make a band logo.
One Million Fans (30) - Reach 1 million fans in World Tour.
Open Road (20) - Win a Bus in World Tour.
Overdrive Overdose (25) - Achieve an 8x Band Multiplier.
Worldwide Sensation (25) - Gain access to every venue in the world.
You Killed the Radio Star (15) - Make a music video in World Tour.
You're Hired! (10) - Hire a staff member.

Unlock Instruments
Simply meet the requirements and the instrument will be immediatly available in the "Instruments" section of "My Closet" in the Rock Shop:

Clear Fender Ameican Deluxe Stratocaster HSS - Join the "Rolling Stone Rock Immortals" list
Gold Fender American Deluxe Stratocaster HSS - Beat the "Impossible Guitar Challenge"