Guitar Hero, which are sadly limited to selling the game to people and then selling extra songs. According to a statement made by Activision Publishing CEO Mike Griffith at the Activision Blizzard Analysts' Day event, the company is looking to branch out into new ways of convincing people to pay more to play something they've already bought. Specifically, a subscription model, separate from the early rumor of a subscription-based online play scheme.
"Looking even further out," Griffith said, "we're exploring new models, like an annual pass subscription where players can subscribe and get a certain number of songs downloadable each month." Now, we make fun of the greed that motivates the annual release schedule, new instruments, piles of DLC, and pretty much everything else about Guitar Hero, but this is actually a cool idea. Like a Netflix for Guitar Hero songs.