Fans have already given us loads of free DLC for New Super Mario Bros. and New Super Mario Bros.Wii, and it looks like Super Mario Galaxy 2 is going to get the same treatment. The project is still very early though. The video above is more of a proof of concept than anything else. I wouldn't want to play that level, but I'm really excited about what that level could lead to.
Are you watching, Nintendo? Once again, your fans are making you look bad. There is no reason why you couldn't be the one's creating a distributing more levels for your games. I really hope you wise up to this fact soon. Your current lack of attention to the DLC world is only working to turn fans off to your business practices, and turn them on to hacking your consoles.