Instructions
Select "Xbox Live Game" from the Castle Crashers main menu.
Join an online game hosted by a player with a level 256 character. Press the "B" button to exit the Xbox Live Game screen if you are partnered with someone without a level 256 character. Continue entering the Xbox Live Game screen to be paired with a new set of partners until you find a level 256 character.
Press "Y" to toggle your ready status while on the Xbox Live Game screen. The icon next to your name will change from red to green. A countdown timer will begin once all players are ready.
Press the "B" button to exit the game when the countdown timer reaches one second. You will exit the game and return to the main menu. Your characters will be increased by 250 levels.