QR Codes, as part of the game environment in the video game Homefront [by THQ] received more than 30,000 scans within the first 48 hours of the games launch. The codes linked to videos which supported the storyline or downloadable content.

I like this extra element of discovery and interactivity which involve you and your mobile device, as if a part of the games plot.

[potential spoiler] List of all the code locations