If you're like the rest of America, your old Rock Band has learned a few new tricks lately.

Over 70 downloadable tracks like "Buddy Holly" and "Wonderwall" have kept mock musicians rocking since the game's November launch, and Harmonix announced today that they have sold over six million of them.

Expect this number to explode in the coming months with Rock Band's new in-game music store. Now that players don't have to jump into Xbox Live Marketplace's clunky interface every time they want to download songs, they'll buy a lot more of them.

"The success of Rock Band downloadable content to date firmly reinforces our vision and its potential as a platform for music discovery," said MTV senior vice president Paul Degooyer in a statement today.

MTV said one more thing about Rock Band sales: For the months of January and February, Rock Band was the top-selling videogame by revenue in the U.S. Of course, that's down to the fact that it's a hundred and seventy freaking dollars.