Super Smash Bros. Brawl: Unlock Coop Events
In Super Smash Bros. Brawl for the Wii, there are 21 total playable coop events. You start off with 1 through 8, and you have to unlock the rest.
Coop Events 9 to 13 – Complete the Subspace stage in Adventure Mode
Coop Events 14 to 20 – Complete 10 coop events and unlock all hidden characters
Coop Event 21 – Complete the first 20 coop events