Unlock All Songs in Rock Band

If you're too lazy to go through career mode to unlock all the songs you can do it this way. This is for Rock Band 1, not RB2.

Steps

Put Rock Band in the slot and turn it on.
Get on drums or guitar.
Pound out the following note sequence if on drums, or on guitar push the following fret buttons quickly in this order: Red, Yellow, Blue, Red, Red, Blue, Blue, Red, Yellow, Blue.
Do it again, faster, correctly, or perhaps slower, if nothing happens. If done correctly a box will pop up telling you that it worked.

It only works the one time you do it. Once you turn off the game you'll have to put the code back in again once you turn it on again.
If you have Rock Band 2, pay the $5 fee to export the Rock Band 1 songs. All 55 exported tracks will be immediately playable from RB2, regardless of whether you unlocked them in the first game. However, three ("Enter Sandman" by Metallica, "Run to the Hills" by Iron Maiden, and "Paranoid" by Black Sabbath) will not export at all, because for various reasons Harmonix could not acquire extended licenses for them (e.g. for Metallica, they'd already signed with Neversoft).

Using this cheat also disables saving so you won't be able to save a career game, save any high scores on the songs, or save any other thing.