Well, this is where I get sent loads of hate mail.
We all know that Smash Bros. is first and foremost about selling other Nintendo games. It's no coincidence that F-Zero X ended up immensely more popular than F-Zero after Captain Falcon's appearance in Super Smash Bros. And it's no coincidence that Fire Emblem finally came to America after Marth and Roy appeared in Melee. Well, now Brawl is going to encourage you to buy Virtual Console copies of the games the characters appearing in Brawl by offering trial versions of the NES, SNES and N64 classics that spawned these characters.
The only games confirmed thus far by the Smash Dojo at SmashBros.com are Ice Climbers, Star Fox 64, Super Metriod, Super Mario Bros., Kirby's Adventure and Kid Icarus. It was implied, though, that more games will be available.